Unriddle the Riddles
by melmonella
Summary: Continuation of "Harry Potter and Methods of Rationality" by Eliezer Yudkovsky. What if Harry allied with Professor Quirrell instead of attempting to kill him through what amounted to sheer dumb luck? What compromise might have been reached?
1. Chapter 1

**Author notes:  
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 **Several people have suggested I post this story here. Well, now it is posted. Enjoy.**

 **Large chunks of the text are copied straight from the original. Copied text has been highlighted with a different color when story was posted on google docs, but does not allow for this functionality.  
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 _Tom Riddle._

The words seemed to echo inside Harry's head, sparking resonances that as quickly died away, broken patterns trying to complete themselves and failing.

 _Tom Riddle is a_

 _Tom Riddle was the_

 _Riddle_

There were other priorities occupying Harry's attention.

Professor Quirrell was pointing a gun at him.

And for some reason Lord Voldemort hadn't fired it yet.

Harry's voice came out in more of a croak. "What is it that you want from me?"

"Your death," said Professor Quirrell, "is clearly not what I am about to say, since I have had plenty of time to kill you if I wished. The fateful battle between Lord Voldemort and the Boy-Who-Lived is a figment of Dumbledore's imagination. I know where to find your family's house in Oxford, and I am familiar with the concept of sniper rifles. You would have died before you ever touched a wand. I hope this is clear to you, Tom?"

"Crystal," Harry whispered. His body was still shaking, running programs more suited to fleeing a tiger than casting delicate spells or _thinking._ But Harry could think of one thing the person pointing a gun at him obviously wanted him to do, a question that person was waiting for him to ask, and Harry did so. "Why are you calling me Tom?"

Professor Quirrell regarded him steadily. "Why _am_ I calling you Tom? Answer. Your intellect is not everything I hoped for, but it should suffice for this."

Harry's mouth seemed to know the answer before his brain could manage to focus on the question. "Tom Riddle is your name. Our name. That's who Lord Voldemort is, or was, or - something."

Professor Quirrell nodded. "Better. You have already vanquished the Dark Lord, the one and only time that you will ever do so. I have already destroyed all but a remnant of Harry Potter, eliminating the difference between our spirits and enabling us to reside in the same world. Now that it is clear to you that the battle between us is a lie, you might act sensibly to advance your own interests. Or you might not." The gun jabbed slightly forward, causing prickles of sweat to appear on Harry's forehead. "Drop your wand. _Now_."

Harry dropped it.

"Step away from the wand," said Professor Quirrell.

Harry obeyed.

"Reach toward your neck," said Professor Quirrell, "and remove your Time-Turner, touching it by the chain only. Place the Time-Turner on the ground, then step away from it as well."

This also Harry did. Even in his state of shock, his mind still looked for a way to spin the Time-Turner in the process, a sudden move that would win; but Harry knew that Professor Quirrell would already be imagining himself in Harry's position, looking for the same possible opportunities.

"Remove your pouch and place it also on the ground, then step away."

Harry did this.

"Very good," said the Defense Professor. "Now. It is time for me to obtain the Philosopher's Stone. I mean to bring along these four first-years here, suitably Obliviated of their most recent memories so that they still recall their original purpose. Snape I shall control and set to guard this door. After this day's work is done, I intend to kill Snape for the betrayals he has offered my other identity. The three heir-children I shall take with me afterwards, to shape their future loyalties. You should also know this, I have taken hostages as insurance in case of a fight with the Headmaster. I have already set in motion a spell that will kill hundreds of Hogwarts students, and it can't be stopped if I am killed or otherwise restrained. I can and will stop that spell using the Stone, if I obtain it successfully. Hogwarts students are a valuable resource, not to be wasted lightly. If I am interrupted before then, or if I choose not to stop the spell, hundreds of students will die." Professor Quirrell's voice was still mild. "Do you yet perceive any interests you have at stake, boy? I would smile to hear you say 'no', but that is too much to hope."

"I'd like," Harry managed to say, through the horror, and the heartbreak, and the knives slicing away at an emotional connection that hurt like living flesh as it was cut, "for you not to do those things, Professor." _Why, Professor Quirrell, why, why did it have to turn out like this, I don't, I don't, I don't want this to be happening…_

"Very well," Professor Quirrell said. "I grant you permission to offer me something I want." The gun gestured invitingly.

Some part of Harry's mind scrabbled frantically, looking for something, anything that might be of more value to Lord Voldemort or Professor Quirrell than child hostages or Severus's death.

Another part of him, the part that had never stopped thinking, already knew his answer.

"You already have an idea for what you want from me," Harry said, through the sickness and the bleeding wounds in his soul. "What is it?"

"Your help in obtaining the Philosopher's Stone."

Harry swallowed. He couldn't stop his eyes from going to the gun, then back up at Professor Quirrell's face. He was aware that the hero in a storybook was supposed to say 'No', but now that he was actually in a situation like this, saying 'No' didn't seem to make sense.

"I am disappointed that you need to think about this," said Professor Quirrell. "It is straightforward that you should obey me for now, since I hold every advantage over you. I have taught you better than this; in this situation you should certainly pretend to lose. You can expect to gain nothing by resisting, except pain. You should have calculated that it was better to answer sooner, and not earn my distrust." Professor Quirrell's eyes studied him curiously. "I hope Dumbledore hasn't filled your ears with nonsense about noble defiance? You should be able to see why that sort of strategy would be entirely pointless, and that I could easily make it seem morally worse than submission, should you nonetheless resort to it. I would prefer not to have to demonstrate how."

Harry took a deep breath, several of them. Whatever part of him kept on running on full automatic was screaming at the remainder of his mind that it _could not afford to stay in shock._ Shocks were of finite duration, neurons kept firing regardless, the only reason Harry's mind would shut down while his brain kept running was if Harry's self-model _believed_ his mind would shut down -

"I don't mean to try your patience," Harry said. His voice was cracking. That was good. Sounding like he was still in shock meant that Lord Voldemort might give him more time. "But if Lord Voldemort had a reputation for keeping his bargains, I don't know about it."

"An obvious concern," Professor Quirrell said. "There is a simple answer, and I would have enforced it upon you in any case. _Ssnakes can't lie_. And since I have a tremendous distaste for stupidity, I suggest you do not say anything like 'What do you mean?' You are smarter than that, and I do not have time for such conversations as ordinary people inflict on one another."

Harry swallowed. Snakes can't lie. " _Two pluss two equalss four._ " Harry had tried to say that two plus two equalled three, and the word _four_ had slipped out instead.

"Good. When Salazar Slytherin invoked the Parselmouth curse upon himself and all his children, his true plan was to ensure his descendants could trust one another's words, whatever plots they wove against outsiders." Professor Quirrell had adopted his lecturing pose from Battle Magic, like someone putting on a well-worn mask, but the gun remained pointed in his hand. "Occlumency cannot fool the Parselmouth curse as it can fool Veritaserum, and you may put that to the trial also. Now listen well. _Come with me, promisse your besst aid in getting Sstone, and I sshall leave thesse children behind unharmed. Hosstagess are real, hundredss of sstudentss die tonight unlesss I sstop eventss already sset in motion. Will sspare hosstagess if I obtain Sstone ssuccessfully._ And mark also this, mark it well: _I cannot be truly sslain by any means known to me, and lossing Sstone will not sstop me from returning,_ _nor sspare you or yourss my wrath sshould you be the causse of that._ I do hope you would cooperate with this venture, since you stand only to gain from it. But I also credit your ability to annoy me by meddling in my plans, and suggest you avoid doing so."

"You said," Harry's voice was strange in his own ears, "that the Philosopher's Stone had different powers from what legend said. You said that to me in Parseltongue. Tell me what the Stone really does, before I agree to help you get it."

"Ah," said Professor Quirrell, and smiled. "You are thinking. That is better, and as a reward I shall offer you a further incentive for cooperation. Eternal life and youth, the creation of gold and silver. Suppose these are true benefits of holding the Stone. Tell me, boy. What is the Stone's power?"

It might have been the adrenaline still in him, being actually useful for his brain for once. It might have been the power of being told that an answer existed, and that the evidence wasn't a lie. "It can make Transfigurations permanent."

Then Harry stopped, as he heard what his own mouth had just said.

" _Correct_ ," hissed Professor Quirrell. "Thus, whoever holds the Philosopher's Stone is able to perform human Transfiguration."

Harry's torn mind was knocked about yet again, as he realized what further incentive would be offered him.

"You stole Miss Granger's remains and Transfigured them into some innocuous-appearing target," said Professor Quirrell. "A Transfigured target that you must keep somewhere about your own person, in order to sustain the Transfiguration. Ah, I see your eyes going to that ring upon your hand, but of course Miss Granger would not be the little jewel set into the ring, would it? That would be too obvious. No, I expect you Transfigured Granger's remains into the ring itself, letting the aura of the Transfigured jewel mask the magic in the Transfigured ring."

"Yes," Harry said, forcing out the word. It was a lie, for once, and Harry's glance had been deliberate. Harry had expected someone to challenge him on the steel ring, he'd tried to provoke that challenge so he could prove to be innocent yet again, though nobody had taken him up on it - maybe Dumbledore had just sensed that the steel by itself wasn't magical.

"Fine and good," said Professor Quirrell. "Now come with me, help me to obtain the Stone, and I will resurrect Hermione Granger on your behalf. Her death has had unfortunate effects on you, and I would not mind undoing them. That, as I understand you, is your greatest desire. I have done you many kindnesses, and I would not mind doing you this one more." A blank-eyed Professor Sprout had now risen from the ground and was pointing her own wand at Harry. " _Help me obtain Sstone of Transsfiguration, and I sshall try my hardesst to ressurrect your girl-child friend to true and lassting life._ "

* * *

Even then.

Even then, with all the world upturned, with shock after shock, even then Harry's brain did not stop being a brain, or completing the patterns its circuits had been wired to complete.

Harry knew that this was too good an offer to make to someone at whom you were pointing a gun.

Unless you _desperately_ needed their help to get the Philosopher's Stone out of the magic mirror.

And there wasn't any time left to plan, only the thought that, if Professor Quirrell really was going this far to get his help - what Harry _wanted_ was to demand Professor Quirrell promise not to kill anyone in the future in exchange for his help now, but Harry had a strong sense that Professor Quirrell would reply 'Don't be ridiculous' and there wasn't time for ordinary conversation Harry had to guess the highest safe request in advance -

And this was when his Ravenclaw side spoke up, and astonished even Harry himself.

 _We are not doing this._

 _What?_ Said Hufflepuff.

 _We were about to ask for the lives of Hogwarts students in return for our help, or something similar, weren't we? How many people do we need to indirectly kill before we will actually start to clearly evaluate the real consequences of our actions?_ Said Ravenclaw.

 _Are you insane? In what way is saving Hogwarts students killing people? That's too much even by my standards,_ said Slytherin.

 _This is not about Hogwarts students, or even Britain_ , answered Ravenclaw. _Remember that time we re-evaluated how dangerous Lord Voldemort was? Now do it again, except take into account this is Professor Quirrell we are talking about. How did we put it? A Dark Rationalist isn't a "threat", they are an extinction event? If Lord Voldemort wanted, he could take over the whole world tomorrow, whatever his reasons for not doing so earlier. We aren't deciding whether dark lord number 498 gets magical artifact of dread power number 38, we are deciding who is going to pretty much single-handedly dictate the future of the whole world._

 _So what are you suggesting?_ said Slytherin. _We throw ourselves at him, get shot and die? That will stop him from taking over the world for sure._

 _Dumbledore, whatever his other faults, isn't a complete idiot,_ answered Ravenclaw, _he has probably set protections around the stone sufficiently dangerous to threaten even Lord Voldemort. This is why the Professor is pointing the gun at you - he needs your help, because he expects a higher chance of success with your help than without. If his utility function is sufficiently incompatible with yours, like if he wants to blow the earth up, then decreasing his chance of successfully obtaining the stone is worth more than the lives of all Hogwarts students taken together._

 _What?_ said Hufflepuff _. You can't trade human lives like that-_

Ravenclaw just flashed an image of Hermione's still body, with "five billion times this" written above it.

NO! internally screamed all of Harry.

 _Then start multiplying like the consequentialist you claim to be,_ said Ravenclaw, _unless you know what kind of future Quirinus Quirrell is going to bring about, you cannot in good conscience help him become more powerful._ _Furthermore, pretty much everything else is overshadowed by the five billion humans at stake here, so almost nothing but his terminal values actually matters._

 _And how do you expect to find those out?_ said Slytherin. _If you ask, he can always ...just...lie..._

Professor Quirrell's eyes narrowed, his lips parted -

"Before I can decide to help you," blurted out Harry, "I need to know what are your terminal goals, Professor."

Professor Quirrell rolled his eyes at this. "While I can appreciate the spirit of not giving up, that is far too blatant even given the pressure you are under. I will not talk about my future plans. Ask something else."

"Not plans, goals. Like..."-Harry struggled to come up with an explanation for "utility function" - "If we were playing chess then your goals could be to win the game, or to teach the other player to play, or something else, while your plans would be the moves you intended to take. Terminal goals are ones that are worth it in and of themselves, and not because they let you achieve some other goal."

Professor Quirrell seemed annoyed. "Are you just wasting time, boy? You can guess at my goals well enough, then. Why are you asking? Answer in parseltongue."

" _Wass not wassting time. If you are the ssort of persson who would want to desstroy the world, or ensslave all humanss, or ssend humanity back to the dark agess, I can not, will not help you. Besst to gamble on Sschoolmasster'ss defencess being too much for you."_

"What part of pretending to lose didn't you learn? If those were my goals, you should still have agreed to help, to best control my actions in the future."

" _No point. Would not have been able to sswear regardlesss, if I wassn't sssure, ssso might as well assk directly."_

Professor Quirrell sighed, and hissed. " _I do not want to die. I want to ssspend my life enjoying myssself without being ssurrounded by idiotsss. Do not want to desstroy the world - thiss isss where I keep my ssstuff, are you a fool boy? Why would I ssseek to dessstroy it? Do not care for humanity one way or another, asss long asss it doessn't interfere with other desssiress. Now are you done wassting time? Make your decisssion now."_

"In return for me helping you," Harry's mouth said, "I want your promise that you do not plan to turn on me when this is over. I want answers, the truth about everything that's been going on this whole time and everything you know about my nature."

The pale blue eyes regarded him dispassionately.

 _I really think we could have thought of something better to ask for than that,_ said Harry's Slytherin side. _But I suppose we were legitimately out of time, and whatever we need to do next, answers will help._

Harry wasn't listening to that voice right now. Cold chills were still going down his spine from hearing the words that had just come out of his lips, addressed to the man with the gun.

"That is your final condition for helping me to obtain the Stone?" said Professor Quirrell.

Harry nodded, unable to form words.

 _"Agreed,_ " hissed Professor Quirrell. " _I do not intend to threaten your life or magic in future, sso long ass you do not become a threat to my life or magic. Help me, and you sshall have ansswerss to your quesstions, sso long ass they are about passt eventss, and not my planss for the future. Now promisse that you will not attempt to warn againsst me or esscape. Promisse to put forth your own besst efforts toward helping me to obtain the Sstone. And your girl-child friend sshall be revived by me, to true life and health; nor sshall me or mine ever sseek to harm her._ " A twisted smile. " _Promisse, boy, and the bargain will be sstruck."_

"I promise," whispered Harry.

 _WHAT?_ screamed other parts of his mind.

 _Um, he's still pointing a gun at us,_ pointed out Slytherin. _We confirmed he wasn't going to wipe away humanity with decent certainty, and so_ _we don't actually have much of a choice in following our personal objectives, we're just getting as much mileage out of this as possible._

 _You bastard,_ said Hufflepuff. _Do you think this is what Hermione would have wanted? This is Lord Voldemort we're talking about, do we even know how many people he's killed, and will kill? You didn't even ask for the safety of your friends!_

 _Both of those things are irrelevant,_ said Ravenclaw, _Voldemort clearly does not care for your friends. Asking for their safety would just sacrifice your, currently extremely limited, political capital with him._

 _Political capital?_ screamed Hufflepuff, _POLITICAL CAPITAL? Do you want to make peace with him, after all he has done?_

 _We probably should,_ said Slytherin _. I mean, suppose that we can get to our win state-conquering the world, stopping death, and so on- just two weeks earlier if we make peace with Quirrell. Either because he directly assists us with his magical lore and intelligence or because we do not waste resources on trying to fight him. The natural death rate in the world is what, around two people per second? If Quirrell killed five people per hour, every hour, and didn't sleep it'd take him sixty years just to break even with the number of people you'd save by agreeing to a truce with him. Now, two weeks is a lower estimate, and from what we know of him he doesn't kill indiscriminately. He would probably only resort to murder if it was convenient or if the person personally offended him, so the actual rates would be significantly lower, and we could decrease them even more. Do you think we wouldn't find a way to keep him away from idiots in sixty years? Or solve the problem permanently, for that matter?_

Professor Quirrell regarded him steadily. "Repeat the full promise in Parseltongue, boy."

" _I sshall help you obtain the Sstone... I cannot promisse I will usse my besst efforts, my heart will not be in it, I fear. I intend to try. Sshall not do anything I think will annoy you to no good end. Sshall call no help if I expect them to be killed by you or for hosstagess to die. I'm ssorry, teacher, but it iss besst I can do."_ Harry's mind was settling, composing itself, as the decision was made. He would stay with Professor Quirrell, go with him to get the Stone, and... and... and Harry didn't know, except that he'd go on thinking. It seemed unlikely that he would die, given the oath professor made.

"You actually are sorry about that?" Professor Quirrell looked amused. "I suppose it shall have to do. Then keep two other things in mind: _I have plan to sstop even sschoolmasster, if he appearss before uss._ And also this: I will occasionally ask you to say in Parseltongue whether you have betrayed me. _The bargain is sstruck._ "

* * *

After that, Professor Sprout picked up Harry's wand, and wrapped it in shimmering cloth; then she placed it on the floor, and again pointed her wand at Harry. Only then did Professor Quirrell lower his gun, which seemed to disappear into his hand, and pick up Harry's wrapped wand, tucking it into his robes.

The True Cloak of Invisibility was removed from the sleeping form of Lesath Lestrange, and Professor Quirrell took the Cloak, as well as Harry's pouch and Time-Turner.

Then Professor Quirrell cast a mass Obliviation followed by the mass version of the False Memory Charm, the one that just had the subject fill in the blanks using their own suggestibility, on all the students present. Afterwards Professor Sprout floated away the sleeping children, now wearing an expression that seemed annoyed and preoccupied, as if they'd been in some Herbology accident.

Professor Quirrell then turned back to where the Potions Master lay sprawled, bent over and placed his wand on Professor Snape's forehead. _"Alienis nervus mobile lignum."_

The Defense Professor stepped back, and began to move his left fingers in the air as though manipulating a puppet on strings.

Professor Snape pushed himself up from the ground by smooth motions, and stood once more before the corridor door.

" _Alohomora,_ " Professor Quirrell said, pointing his wand at the forbidden door. The Defense Professor looked rather amused. "Would you do the honors, boy?"

Harry swallowed. He was once again having second thoughts, and third thoughts.

He composed himself. Numbers didn't lie. Whatever hesitation he was feeling was coming from his emotional side, that deontological mode that the human brain fell into all too easily. The consequences of his choices seemed clear enough, which was the important thing.

Harry laid his hand on the door-knocker, and took several deep breaths, again composing his mind as best he could. Go through with it, don't get shot, be there to optimize events, be there to watch for opportunities and stay capable of taking them. It wasn't a great choice, but all the other ones seemed significantly worse. Just think, if he was just a little less sane he might have actually considered attempting to kill Voldemort, and would have lost all the protection the oath the Professor gave afforded him.

Harry pushed open the forbidden door, and stepped through.


	2. Chapter 2

After a single step into Dumbledore's forbidden chamber, Harry shrieked and jumped back and collided with Professor Snape, sending the two of them down in a heap.

Professor Snape picked himself up and resumed standing in front of the door. His head tracked to look at Harry. "I am guarding this door at the Headmaster's orders," said Professor Snape in his usual sardonic tones. "Be off with you at once, or I shall deduct House Points."

This was bone-chillingly creepy, but Harry's attention was occupied by the gigantic three-headed dog which had lunged forward, only to be stopped meters from Harry by the chains upon its three collars.

"That - that - that - " Harry said.

"Yes," Professor Quirrell said from a ways behind him, "that is indeed the usual occupant of that chamber, which is off-limits to all students, especially first-years."

 _"That's not safe even by wizard standards!"_ Within the chamber, the enormous black beast gave a multi-voiced bellow, flecks of white saliva flying from three fanged mouths.

Professor Quirrell sighed. "It is enchanted not to eat students, just spit them back out through the door. Now, boy, how would you recommend that we deal with this dangerous creature?"

"Uh," Harry stuttered, trying to think over the continued roaring of the chamber's guardian. "Uh. If it's like the Cerberus from the Muggle legend of Orpheus and Eurydice, then we have to sing it to sleep so we can pass -"

" _Avada Kedavra._ "

The three-headed beast fell over.

Harry looked back at Professor Quirrell, who was giving him a look of extreme disappointment, as if to ask whether Harry had attended any of his classes, ever.

"I sort of _assumed_ ," Harry said, still trying to catch his breath, "that going through this challenge in any way except the one used by first-years, might perhaps trigger an _alarm_."

"That is a lie, boy, you simply did not remember your lessons when you faced the occasion in true life. As for alarms, I have spent months befuddling all the wards and tripsigns upon these chambers."

"Then why did you send me in first, exactly?"

Professor Quirrell just smiled. It looked significantly more evil than usual.

"Never mind," Harry said, and walked slowly into the chamber, his limbs still shaking.

The chamber was all of stone, illuminated by a pale blue light that shone from arched nooks carved into the wall; as if the light of a grey sky were passing through windows, though there were no windows. At the far end of the chamber was a wooden trapdoor upon the floor, with a single ring attached. In the middle of the chamber lay a gigantic dead dog with three lifeless heads.

Harry turned toward one of the arched nooks and looked inside it. There was nothing there but the sourceless blue glow, so he walked over and looked in the next one, also scrutinizing the wall as he passed.

"What," said Professor Quirrell, "are you doing?"

"Searching the room," Harry said. "There could be a clue, or an inscription, or a key we'll need later, or something -"

"Are you serious, or are you deliberately trying to slow us down? Answer in Parseltongue."

Harry looked back. " _Wass sseriouss,_ " hissed Harry. " _Would have done ssame if came by mysself._ "

Professor Quirrell briefly massaged his forehead. "I confess," he said, "that your approach would serve you well in, say, exploring the tomb of Amon-Set, so I will not quite call you an idiot, but still. The false puzzle, the outer form of the challenge, is a game meant for first-years. We simply go down through the trapdoor."

Beneath the trapdoor was a gigantic plant, something like an enormous dieffenbachia with wide leaves emerging from the central stem like a spiral staircase, but darker-colored than a normal dieffenbachia, with tendril-like vines emerging from the central stem and hanging down. The base spread out wide with bigger leaves and tendrils, as though promising to cushion anyone's fall. Beneath was another stone chamber like the first, with the same nooks like false arched windows, emitting the same grey-blue light.

"The obvious thought is to fly down on the broomstick in my pouch, or toss something heavy to see if those tendrils are traps," Harry said, peering down. "But I'm guessing you'll say that we just walk down the leaves." They certainly looked like they were meant to be a spiral staircase.

"After you," said Professor Quirrell.

Harry carefully put a foot down on a leaf and found that it indeed supported his weight. Then Harry took a last look around the room before departing, to see if there was anything worth noticing.

The enormous dead dog called enough attention to itself that it was hard to focus on anything else.

"Professor Quirrell," Harry said, omitting the phrase _your approach to dealing with obstacles has certain drawbacks,_ "what if somebody looks in the door and sees that the Cerberus is dead?"

"Then they have probably already noticed something wrong with Snape," said Professor Quirrell. "But since you insist..." The Defense Professor walked over to the three-headed corpse and placed his wand against it. He began a Latin-sounding incantation that was accompanied by a sense of rising apprehension, the Boy-Who-Lived feeling the Dark Lord's power as he always had.

The last word spoken was _"Inferius"_ and it was accompanied by a final surge of _STOP, DON'T_.

And the three-headed dog rose to a stand, its six eyes dull and blank, turning to watch the door once more.

Harry stared at the huge Inferius with a horrible sinking sensation in his stomach, the third-worst feeling he'd ever felt in his life.

He knew then that he'd seen and sensed this procedure before, only without the spoken Latin.

The centaur who'd confronted him in the Forbidden Forest was dead. The Defense Professor had hit it with a real Avada Kedavra, not a fake one.

He squashed it down. Gathered all parts of him that were feeling guilty about the whole issue into one big ball and set it on fire. From the talks Harry had with the various Wizards, he was pretty much the only one who seemed bothered by the issue of death. If there was anyone, anyone at all who would be motivated to do something about it as soon as possible, it would be him. The lives he had to save were the thousands that died every day, not the single ones that he was personally involved in.

Somewhere in the back of his mind, Harry wondered wherever he could have done better. Saved that life too, among others. Could he have discussed his preferences in combat resolution with Professor Quirrell after Azkaban, perhaps? Pointed out that a dead enemy could not be questioned for information, so it was generally preferable to take enemies alive if your ability significantly surpassed theirs? Even if you weren't going to abide by Geneva convention regarding the treatment of prisoners, you could easily kill them after interrogation. He still remembered what the professor said in the infirmary - that Harry wasted an opportunity to learn the secrets of magic from the most creative mage of his generation by just never thinking to ask for private lessons. How many opportunities to save lives could you really waste by not using every opportunity at your disposal to its fullest?

Harry said nothing aloud. The Defense Professor would either confirm the accusation in Parseltongue or lie in plain speech, and either way the Defense Professor would have more reason to suspect Harry's next actions. But Harry knew that - although he didn't know _how_ he would convert Professor Quirrell to his view of thinking - there could hardly be an amicable settlement between him and Lord Voldemort, for those two different spirits could not exist in the same world. He would make Quirrell desire the better future for the whole world or he would die trying.

And it was like that resolution, that knowledge of opposition, invoked a strength from what Harry had thought of as his dark side. Harry had stopped trying to call deliberately on his dark side after the day he'd killed the troll. But his dark side had never been something separate from him. It had been something remembered from Tom Riddle. Harry didn't know how that had happened, but taking the assumption and running with it, whatever echoes of cognitive skill were in his dark side should be there for him to use. Not as a separate mode, as Harry had conceptualized at first, but just as neural patterns with a strong tendency to chain into one another since they had once formed part of a connected whole.

This unfortunately did not change that Professor Quirrell had the same skills with far more life experience backing them up, and also had the gun.

Harry turned, and set foot on the giant plant, and began to walk down the spiral staircase provided by the leaves. His mind, having abandoned his naive childish sensibilities, kept working. Emotionally, he hated having to deal with Voldemort, hated the fact that in all likelihood, there would be no way to convince him to adopt a pacifistic approach to problems. But life was not a story. There didn't have to be a way to stop Voldemort from killing people _and_ return Hermione to life _and_ save the hostages _and_ ensure that death is defeated. You had to pick things you could change in order to do the most good, and then hammer at them with all your might until they gave way to a better world. And that meant letting some smaller things remain unchanged.

Harry continued his descent.

Behind him, the three-headed dog waited, guarding the gate.


	3. Chapter 3

The spiraling leaves of the gigantic dieffenbachia felt like forest loam beneath Harry's shoes, not as unyielding as concrete, but supporting his weight. Harry kept a wary eye on the tendrils, but they remained passive.

His brain kept working. Was there anything he could do now, this moment, to improve his chances of achieving a better world? Any information or power he could acquire?

Well, one thing was rather obvious.

"Professor," said Harry, "you said you would answer my questions. Why did you not just ask for my help in getting the stone before today? I have said before that I have a preference for you being alive rather than dead. You also know I want immortality for myself and others. I would have obviously cooperated with such a venture, so why risk confrontation and point a gun at me?"

"Why do you think, mister Potter? I believe you to be too naive to be trusted with such matters. I couldn't reliably predict what you would do in the event that I came out as being Voldemort, and knew you would not agree to what needed to be done to distract the Headmaster sufficiently so that he was no longer an obstacle to getting the stone. As such, I had to force you into a scenario where you couldn't do something foolish like call for help before hearing me out. Really, you should have guessed as much already."

That… Was not entirely implausible. If only there was a way to make sure Professor Quirrell wasn't lying…

Oh, right. Magic.

" _Confirm in sspeech,_ " hissed Harry

" _All of that iss true,_ " hissed Voldemort back.

Harry considered this. If that really was true, then the obvious next question would be…

"So you have threatened me at gunpoint just to prevent me from casting magic, or timeturning away?"

" _Ssomething along thosse liness. Was no malice in it, regardlesss. Pluss, I found it amussing."_

Well. This meant that Voldemort did not suddenly become stupid, and that meant he could be negotiated with, even if Hufflepuff was screaming in indignation at that.

" _Well then. If you promisse to allow me to usse the sstone for my own projectss after we acquire it,"_ , Harry hissed, " _in exchange for knowledge or magic unique to me, under termss that would be conssidered fair by both of uss, and in ssuch a fasshion ass to not threaten your immortality… I could sswear to usse my full effortss to acquire the sstone, and not attempt any betrayal that would decreasse our chancess of acquiring it."_

Even if in the worst case scenario where the stone itself couldn't be replicated, it could still be used to save massive numbers of people. Besides the trivial case of healing diseases by transfiguring people, it could make chemical substances produced with transfiguration permanent, which would still help massively. Even just a single adult wizard with it could probably produce a perfect space elevator cable out of transfigured nanotubes, or a whole cistern of an expensive medical drug.

Professor Quirrell hummed, "Perhaps. I stand to lose little from this arrangement. And you would agree to this? To letting me, the murderer of hundreds, possess the stone uncontested? After I've taken hostage the lives of hundreds of students?"

Harry shrugged "I can save more lives with one hour of stone usage than you have ever killed or will kill, even if you go on a rampage," Harry considered that, " _small_ rampage, in any case. Whatever my emotions are saying, I should minimise lives lost, not worry about whether you seem evil. Leaving the stone stuck inside the mirror goes contrary to that, and Dumbledore would hardly let me access it otherwise."

Professor Quirrell chuckled, "Well, what do you know. You are actually capable of learning. Who knows, maybe in time you will abandon your naive sensibilities entirely. _In exchange for your full effortss in acquiring the sstone, and your oath to not attempt any betrayal that would decreasse our chancess of acquiring the sstone during thiss operation, I sswear to allow you to usse the sstone for your own projectss after we acquire it in exchange for knowledge or magic unique to you, under termss that would be conssidered fair by both of uss, and in ssuch a fasshion ass to not threaten my own immortality._ "

Harry smiled, and hissed his own oath. Step one for plan Make Voldemort Relatively Peaceful done. Now to come up with the rest of the steps.

When Harry reached the bottom of the leafy spiral staircase, the tendrils suddenly whipped out and grasped Harry's arms and legs.

After a brief struggle, Harry allowed himself to go limp.

"Interesting," said Professor Quirrell, as he floated down from above, not touching any of the plant's leaves or tendrils. "I notice that you seem to have no trouble losing to a plant."

Harry looked more closely at the Defense Professor, seeing him now without the lens of panic. Professor Quirrell was upright and moving, flying without apparent difficulty; the sense of doom about him was strong. But his eyes were still sunken in the skull, his arms thin and wasted. The sickness had _not_ been bluff, and the obvious hypothesis was that the Defense Professor had recently eaten another unicorn to temporarily regain some strength.

"You specifically let me walk into this trap, Professor," Harry answered, just the way he'd have spoken to Professor Quirrell under normal circumstances. "On my own, I'd have used my broomstick."

"Perhaps. How would an ordinary first-year solve this challenge? If they had their wand, that is." The plant was now reaching tendrils out toward Professor Quirrell, but Professor Quirrell was hovering just out of their reach.

Harry had now remembered Professor Sprout talking about a Devil's Snare plant, which the Herbology textbook had said liked cool, dark places like caves - though how that could be true of a leafy plant was anyone's guess. "At a guess, I'd say this is a Devil's Snare plant and it might retreat from light or heat. So maybe a first-year could use _Lumos_? Today I'd use _Inflammare_ , but I didn't learn that spell until May."

A twirl of the Defense Professor's wand, and a pattern of sprays of liquid shot out from it, striking the plant near the bases of its tendrils, hitting with a quiet splat and then a quiet hissing. All the tendrils touching Harry frantically shot back and began to beat at the growing wounds appearing on the plant's skin, as if trying to remove the pain-stimulus; something about the plant gave the impression that it was screaming soundlessly.

Professor Quirrell finished drifting downward. "Now it is afraid of light, heat, acid, and me."

Harry stepped off the final leaves onto the floor, after a careful glance at his robes and then the floor to make sure that none of the acid had splashed anywhere. Harry had begun to suspect that Professor Quirrell was trying to make some sort of point, but Harry did not know what that point might be. "I thought we were on a mission, Professor. I can't stop you, but is it _smart_ to spend this much time on messing with me?"

"Oh, we have time," said Professor Quirrell, sounding amused. "There would be a great uproar if we were discovered here, guarded by an Inferius. You did not act like you had heard of such an uproar at your Quidditch match, before you arrived in this time and spoke to Snape as you did."

A slight chill came over Harry, as he comprehended this. "Ah. I see. Is there a general technique to using time travel tactically to ensure your success?"

Professor Quirrell chuckled "None that I would care to tell you at this point in time, mister Potter."

And even so... even so it seemed to Harry that if he stood in Professor Quirrell's shoes, he would not be having leisurely conversations and playing mind games. Professor Quirrell was gaining _something_ by taking his time here. But what? Was there some other process that had to run to completion?

"By the by, have you betrayed me yet?" said Professor Quirrell.

 _"Have not betrayed you yet,_ " Harry hissed, " _Have you betrayed me yet?_ "

Professor Quirrell sounded amused. "I suppose it is only fair. _Have not betrayed you yet._ "

The Defense Professor gestured pointedly, and Harry walked ahead to the great wooden door at the end of the room, and opened it.

* * *

The next chamber was smaller in diameter, with a higher ceiling. The light shining out of the arched alcoves was white, instead of blue.

Around them whizzed hundreds of winged keys, beating frantically through the air. After watching for a few seconds, it became clear that only a single key was the golden color of a Snitch - though it was moving slower than a Snitch in a real Quidditch game.

On the other end of the room was a door containing a large, prominent keyhole.

Against the left wall leaned a broomstick, the school's workhorse Cleansweep Seven.

"Professor," Harry said, staring up at the clouds and flocks of whizzing keys, "What exactly is all this about? If you think you've secured a door so that it won't open without a key, you keep the key in a safe place and only give a copy to authorized entrants. You don't _give the key wings_ and then _leave a broomstick propped against the wall._ So what the heck are we doing in here and what is going on? It's an obvious guess that the magic mirror is the only real factor guarding the Stone, but why the rest of this - and why encourage first-years to come here?"

"I am truly not sure," said the Defense Professor. He had entered the room and taken up station well to Harry's right, maintaining the distance between them. "But I shall answer, as I said I would. Dumbledore's way is to do a dozen things which seem mad, and then only eight of them, or perhaps nine, conceal an inner meaning. My guess is that Dumbledore intends to make it seem like I am invited to send a student as my proxy. Precisely so that Lord Voldemort, as Dumbledore conceives of him, is less tempted to think himself clever by doing so. Imagine Dumbledore first considering the issue of how to ward the Stone. Imagine Dumbledore considering whether to set true dangers to guard the Mirror. Imagine him imagining some young student blundering through those dangers at my behest. I think that is what Dumbledore is trying to avoid, by making it seem as though that strategy is invited, and so not cunning. Unless, of course, I have misunderstood what Dumbledore thinks Lord Voldemort will think." Professor Quirrell grinned, and it looked just as natural, on him, as any grin he'd shown Harry before. "Plotting does not come naturally to Dumbledore, but he tries because he must. To that task Dumbledore brings intelligence, dedication, the ability to learn from his mistakes, and an utter lack of native talent. He is marvelously hard to predict for that reason alone."

Harry turned away, looking at the door on the opposite side of the room. _It wasn't a game to him, Professor._ "My guess is that the intended solution for first-years is to ignore the broomstick and use _Wingardium Leviosa_ to grab the key, since this isn't a Quidditch game and there are no rules forbidding that. So what absurdly overpowered spell are you going to unleash on this one, then?"

There was a brief silence but for the whizzing of keys.

Harry took several steps away from Professor Quirrell. "I probably shouldn't have said that, should I."

"Oh, no," Professor Quirrell said. "I think that is a quite reasonable thing to say to the most powerful Dark Wizard in the world when he is standing not a dozen paces from you."

Professor Quirrell put his wand back into the sleeve of his other hand, the hand that sometimes held the gun.

Then the Defense Professor reached into his mouth and took out what appeared to be a tooth. He tossed the false tooth high in the air, and when it came down, it had transformed into a wand that sparked a strange sense of recognition in Harry's mind, as though some part of him recognized that wand as being... part of him…

 _Thirteen and a half inches, yew, with a core of phoenix feather._ Harry had memorized the information when the wandmaker Olli-something had given it, because it had seemed like it might be Plot-Relevant. The event, and the thinking that had underlain it, both felt a lifetime distant.

The Defense Professor raised that wand, and traced in the air a flaming rune that was all jagged edges and malevolence; Harry took another instinctive step back. Then Professor Quirrell spoke. "Az-reth. Az-reth. Az-reth."

The flaming rune began pouring out fire that was... _twisted,_ as though the jagged edges of the rune had become the nature of the fire itself. The fire was blazing crimson, shaded further red than blood, glowing as searingly intense as an arc-welder. That brilliance in that shade seemed _wrong_ in its own right, like nothing shaded so far red should give off that much light; and the searing crimson was shot through with veins of black that seemed to suck the light from the fire. Within the blackened fire, outlined in the interplay of crimson and darkness, animal shapes twisted wildly from one predator to another, cobra to hyena to scorpion.

"Az-reth. Az-reth. Az-reth." When Professor Quirrell had repeated the word six times, as much black-crimson fire had poured out as the volume of a small bush.

The cursed fire slowed in its changes as Professor Quirrell locked eyes upon it, taking on a single form, the form of a blackened blood-burning phoenix.

And something told Harry with a terrible certainty that if that black burning phoenix met Fawkes, the true phoenix would die and never be reborn.

Professor Quirrell made a single gesture with his wand, and the blackened fire went soaring across the room. It met the door and its keyhole, and with a single sweep of crimson-burning wings, most of the door and part of the archway was consumed. Then the tainted crimson blaze swept on.

Harry had only a glance through the hole to see huge statues just beginning to raise swords and clubs, when the blackened fire came among them, and they cracked and burned.

When it ended, the blackened-fire phoenix swept back in through the hole, and hovered above Professor Quirrell's left shoulder, the sun-intense crimson claws staying an inch from his robes.

"Go on ahead," said Professor Quirrell. "It's safe now."

Harry walked forward, needing to invoke his dark side's cognitive patterns in order to maintain calm enough to do it. Harry stepped over the glowing edges of the remaining part of the door, and gazed at a chessboard of ruined huge chess-pieces. The alternating tiles of black and white marble on the floor started five meters after the ruined doorway, and extended from wall to wall, but stopped five meters short of the next door on the opposite side of the room. The ceiling was significantly higher than any of the statues should have been able to reach.

"I would guess," Harry said, and his dark side's cognitive patterns kept his voice calm, "that the intended solution is to fly over the statues using the broomstick from the previous room, since it wasn't actually needed to get the key?"

From behind, Professor Quirrell laughed, and it was Lord Voldemort's laugh. "Proceed," said a voice grown colder and higher. "Go to the next room. I wish to see what you will make of what is there."

 _Arranged by Dumbledore for first-years,_ Harry reminded himself, _it WILL be safe,_ and he walked across the ruined chessboard, laid his hand upon that door's handle, and pushed it inward.

* * *

Half a second later, Harry slammed the door and leapt back.

It took Harry several seconds to master his breathing, and master himself. From behind the door came continued loud bellows, and great slams as of a rock club pounding the floor.

"I suppose," Harry said in a voice grown cold as well, "that since Dumbledore would hardly put a real mountain troll in there, the next challenge is an illusion of my worst memories. Like a Dementor, with the memory projected into the outside world. Very amusing, Professor."

Professor Quirrell advanced himself toward the door, and Harry stepped well aside. Besides the sense of doom that was now strong about the Professor, Harry's dark side or just plain instinct was advising him not to get anywhere near that black-crimson fire hovering above Professor Quirrell's shoulder.

Professor Quirrell swung open the door, and looked in. "Hm," Professor Quirrell said. "Just the troll, as you say. Ah, well. I had hoped to learn something about you more interesting than that. What lies within is a Kokorhekkus _,_ also known as the common boggart."

"A boggart? What does that - no, I suppose I know what it does."

"A boggart," Professor Quirrell said, and now his voice was again that of a Hogwarts Professor lecturing, "gravitates to dark enclosures that are rarely opened, such as a neglected cupboard in the attic. It seeks to be left alone, and it will manifest in whatever form it thinks will scare you away."

"Scare me away?" Harry said. "I _killed_ the troll."

"You leapt backward out of the room without thinking. A boggart seeks out the instinctive flinch, not the reasoned threat. Else it would have selected something more believable. In any case, the standard counter-Charm for a boggart is, of course, Fiendfyre." Professor Quirrell gestured, and the blackened fire leapt off his shoulder and poured through the doorway.

From within the room there was a single squeak, and then nothing.

They advanced into the boggart's former room, Professor Quirrell going first this time. With the seeming mountain troll gone, the room was just another huge chamber lit by sconces of cold blue light.

Professor Quirrell's gaze seemed distant, thoughtful. He crossed the room without waiting for Harry, and swung open the door on the opposite wall of his own accord.

Harry followed after, and not closely.

* * *

The next chamber contained a cauldron, a rack of bottled ingredients, chopping boards, stirring sticks, and the other apparatus of Potions. The light coming from the arched alcoves was white instead of blue, presumably because color vision was important to Potions-brewing. Professor Quirrell was already standing next to the brewing apparatus, scrutinizing a long parchment he had picked up. The door to the next chamber was guarded by a curtain of purple fire that would have looked a lot more threatening, if it hadn't seemed pale and weak by comparison to the blackened flame hovering over Professor Quirrell's shoulder _._

Harry's suspension of disbelief had already checked out on vacation at this point, so he didn't say anything about how real-world security systems had the goal of _distinguishing_ authorized from unauthorized personnel, which meant issuing challenges that behaved _differently_ around people who were or weren't supposed to be there. For example, a _good_ security challenge would be testing whether the entrant knew a lock combination that only authorized people had been told, and a _bad_ security challenge would be testing whether the entrant could brew a potion according to written instructions that had been helpfully included.

Professor Quirrell tossed the parchment toward Harry, and it fluttured to the ground between them. "What do you make of this?" said Professor Quirrell, who then stepped back so that Harry could come forward and pick up the parchment.

"Nope," Harry said after skimming the parchment. "Testing whether the entrant can solve a ridiculously straightforward logic puzzle about the order of the ingredients is still not a challenge that behaves differently for authorized and unauthorized personnel. It doesn't matter if you use a more interesting logic puzzle about three idols or a line of people wearing colored hats, you're still completely missing the point."

"Look at the other side," said Professor Quirrell.

Harry turned over the two-foot parchment.

On the other side, written in tiny letters, was the _longest_ list of brewing instructions Harry had ever seen. "What on Earth-"

"A _potion of effulgence,_ to quench the purple fire," Professor Quirrell said. "It is made by adding the same ingredients, over and over again, in slightly different ways. Imagine some eager young group of first-years, passing all the other chambers, thinking they are just about to reach the magic mirror, and then encountering this task. This room is the handiwork of the Potions Master indeed."

Harry glanced pointedly at the blackfire shape on Professor Quirrell's shoulder. "Fire can't beat fire?"

"It can," said Professor Quirrell. "I am not sure it should. Suppose this room is trapped?"

Harry did _not_ want to be stuck brewing this potion for laughs, or for whatever other reason Professor Quirrell was taking them through these chambers so slowly. The potions recipe had _thirty-five_ separate occasions for adding bellflowers, fourteen times to add 'a lock of bright hair'... "Maybe the potion gives off a lethal gas that is fatal to adult wizards but not children. Or any of a hundred other deadly tricks, if we're suddenly being serious. Are we being serious?"

"This room is the handiwork of Severus Snape," Professor Quirrell said, once more looking thoughtful. "Snape is not a bystander in this game, not quite. He lacks Dumbledore's intelligence, but possesses the killing intent that Dumbledore never had."

"Well, whatever's going on here, it doesn't actually keep out children," Harry observed. "Lots of first-years made it through. And if you can somehow keep out everyone _except_ children, then that, from Dumbledore's perspective, forces Lord Voldemort to possess a child to enter. I don't see the point, given their goals."

"Indeed," Professor Quirrell said, rubbing the bridge of his nose. "But see, boy, this room lacks the triggers and tripsigns that are upon the others. There are no subtle wards to be defeated. It is as if I am _invited_ to bypass the Potion and simply enter - but Snape knows that Lord Voldemort will perceive this. If in fact there was a trap laid for anyone who did not brew the potion, then it would be wiser to lay wards, and give no sign that this room was different from the others."

Harry listened, frowning in concentration. "So... the only point of leaving off the detection webs is to make you _not_ bulldoze this room."

"I expect Snape expects me to deduce that as well," the Defense Professor said. "And past that point I cannot predict at what level he thinks I will play. I am patient, and I have given myself plenty of time for this endeavor. But Snape does not know me, he only knows Lord Voldemort. He has sometimes seen Lord Voldemort shriek in frustration, and act on impulses that appear counterproductive. Consider this matter from Snape's perspective: it is the Potions Master of Hogwarts telling Lord Voldemort to be patient and follow instructions if he wants to enter, as though Lord Voldemort were a mere schoolboy. I would find it easy to comply, smiling the while, and take my vengeance later. But Snape does not know that Lord Voldemort finds it easy to think this way." Professor Quirrell looked at Harry. "Boy, you saw me floating in the air by the Devil's Snare, did you not?"

Harry nodded. Then he noticed his confusion. "My Charms textbook says that it's impossible for wizards to levitate themselves."

"Yes," said Professor Quirrell, "that is what it says in your Charms textbook. No wizard may levitate themselves, or any object supporting their own weight; it is like trying to lift yourself up by your own bootstraps. Yet Lord Voldemort alone can fly - how? Answer as quickly as you can."

If the question was answerable by a first-year student - "You had someone else cast broomstick enchantments on your underwear, then you Obliviated them."

"Not quite," said Professor Quirrell. "The broomstick enchantments require a long narrow shape, which must be solid. Cloth will not do."

Harry's eyebrows furrowed. "How long does the shape have to be? Can you attach some short broomstick rods to a fabric harness, and fly using those?"

"Indeed, at first I strapped enchanted rods to my arms and legs, but that was only to teach myself a new mode of flight." Professor Quirrell drew back the sleeve of his robes, revealing the bare arm. "As you can see, I have nothing up my sleeve right now."

Harry absorbed this further constraint. "You had someone cast broomstick enchantments on your _bones?_ "

Professor Quirrell sighed. "And that was one of Voldemort's most feared feats, or so I am told. After all these years, and some amount of reluctant Legilimency, I still do not truly comprehend what is _wrong_ with ordinary people... But you are not one of them. It is time for you to begin contributing to this expedition. You have known Severus Snape more recently than I. Tell me your own analysis of this room."

Harry hummed, looking thoughtful. "Give me a minute. This requires deliberation."

Professor Quirrell nodded, and leaned against a wall to wait.

The silence stretched. A minute passed, and then another.

"Have you thought of anything yet?" said Professor Quirrell.

"Maybe," said Harry. "Severus, at least the modern-day Severus, respects your intelligence a great deal. I think... I think he might _expect_ Voldemort to believe that Severus wouldn't believe that Voldemort could pass his test of patience, but Severus _would_ expect Voldemort to pass it."

Professor Quirrell nodded. "That is a plausible theory. Do you believe it yourself? Answer in Parseltongue."

 _"Yess, I think,_ " Harry hissed. "Therefore, the point of this room is to delay Lord Voldemort for an hour. And if I wanted to kill you, believing what Dumbledore believes, the obvious thing to try would be a Dementor's Kiss. I mean, they think you're a disembodied soul - are you, by the way?"

Professor Quirrell was still. "Dumbledore would not think of that method," the Defense Professor said after a time. "But Severus might." Professor Quirrell began to tap a finger against his cheek, his gaze distant. "You have power over Dementors, boy, can you tell me if there are any nearby?"

Harry closed his eyes. If there were voids in the world, he could not feel them. "None that I can sense."

"Answer in Parseltongue."

" _Do not ssensse life-eaterss_ _, but it iss posssible they could be hidden from me. Do not know the exact sspecificss of the ability._ "

"Perhaps. Perhaps there is some means by which Dementors might be concealed, being told to leap out and eat a possessing soul if they see one..." Professor Quirrell was still tapping his cheek. "It is not impossible that I would qualify. Or it can be told to eat anyone who passes through this room too quickly, or anyone who is not a child. Bearing in mind that I hold Hermione and hundreds of other students hostage over you, would you use your power over Dementors to defend me, if a Dementor unmasked itself? Answer in Parseltongue."

" _Don't know,_ " Harry hissed.

" _Life-eaterss cannot desstroy me, I think,_ " hissed Professor Quirrell. " _And I will ssimply abandon thiss body if they approach too closse. Sshall return sswiftly thiss time, and then there will be no sstopping me. Will torture your parentss for yearss, to punissh you for balking me. Hundredss of hosstage sstudentss die, including thosse you call friendss. Now I assk again. Will you usse power over life-eaterss to protect me, if life-eaterss come?_ "

A flash of irritation came over Harry's mind, and his mouth opened before he could stop it.

"Are you perhaps tired of life, professor, or is there some deeper reason why you are sabotaging your own prospects for living?"

Professor Quirrell went still, and hissed, sounding like a cobra rearing up to strike. " _Explain yoursself, boy, and I do hope you have a reasson here."_

Well, no taking that back. May as well go all the way now. Harry sighed, and spoke in the best Lecturing Professor voice he could manage. "The Patronus charm, otherwise known as the guardian charm, is known to be difficult to learn even for accomplished Wizards. This is not, however, due to it requiring significant magical reserves, as it is cast using a surprisingly small amount of magic for the effect it produces. Rather, this is because of the strong emotional impression required to cast it. The wizard has to imagine a happy thought or memory during the casting, which can be tricky to achieve while under the effects of a dementor. Because of this, it is easiest to cast in calm, peaceful conditions, and only a fool would try to do so while having death and torture on their mind. One can reasonably conclude that the second version of the guardian charm, one strong enough to destroy dementors, would require an even stronger emotion, and would thus be even harder to perform under those conditions. And to achieve a similar effect wandlessly a yet stronger emotion would be required. How foolish would it therefore be to try doing so while being threatened with torture of all your loved ones?"

Harry turned completely to face Professor Quirrell and hissed. " _I ssaid I don't know. Need emotion for guardian charm, and emotionss ssay to kill you at the firsst opportunity. On an intellectual level I can work with you, becausse I ssee it givess better ressultss. But do not know if I could musster the right emotion in the moment of an attack, I do not have perfect control over them. And you have jusst made it harder. Know you fear death more than anything elsse, but that doess not excusse becoming sstupid when reminded of the posssibility."_

Professor Quirrell's gaze clashed with Harry's, and they stared one another down for a while. Finally, professor Quirrell closed his eyes and sighed. "Well, I do feel the fool now. You speak truth, boy. I shall avoid threatening you for the rest of the mission."

And in the back of Harry's mind, there was one nagging question. Professor Quirrell has said he would just abandon this body if a dementor came. But if his wand stayed connected to his life and magic no matter where his ghost tried to flee, then it would do absolutely nothing.

 _Just how scared of death was Professor Quirrell, that he would miss such an obvious mistake?_

Professor Quirrell smiled. "That reminds me. Have you betrayed me yet?"

" _Have not betrayed you yet._ "

Professor Quirrell went over to the Potions equipment, and began chopping a root one-handed, the knife moving almost invisibly fast and with no apparent effort. The Fiendfyre phoenix drifted over to the opposite corner of the room and waited there. "All matters considered in their uncertainty, it seems wiser to expend the time to pass this room as a first-year would. That might also let you recover enough emotional stability to repel a dementor, should one come," said the Defense Professor. "We may as well talk while we are waiting. You had more questions, boy? I said that I would answer them, so ask."


	4. Chapter 4

The Defense Professor had set up a cauldron, floating it into place with a wave of his wand, another wave starting a fire beneath it. A brief circling of the Defense Professor's finger had set in motion a long-handled spoon, and it had continued stirring the cauldron without being held. Now the Defense Professor was measuring out a heap of flowers from a large jar, what Harry supposed to be bellflowers; the indigo petals seemed luminous in the white light of the walls, and curved inward in a way that gave the impression of a desire for privacy. The first of these flowers had been added to the potion at once, but then the cauldron had just gone on stirring itself for a while.

The Defense Professor had assumed a position from which he could see Harry just by turning his head slightly, and Harry knew that he was within the Defense Professor's peripheral vision.

In the corner a Fiendfyre phoenix waited, some of the nearby stone beginning to gloss over as it melted to greater smoothness. The burning wings shed crimson light that gave everything in the room a tint of blood, and reflected in scarlet sparks from the glassware.

"Time is wasting," said Professor Quirrell. "Ask your questions, if you have them."

Harry's bottled up emotional side kept screaming. _Why, Professor Quirrell, why, why must you be this way, why make yourself the monster, why Lord Voldemort…_

That was what Harry's brain wanted to know.

What Harry _needed_ to know was... some way to control what was going to happen next.

But the Defense Professor had said that he wouldn't talk about his future plans. It was strange enough that the Defense Professor was willing to talk about _anything,_ that had to contradict one of his Rules…

"I'm thinking," Harry said aloud.

Professor Quirrell smiled slightly. He was using a pestle to grind the potion's first magical ingredient, a glowing red hexagon. "I _quite_ understand," said the Defense Professor. "But do not think over-long, child."

Harry closed his eyes. Voldemort did not share his goals, that much was blindingly apparent. Indeed, some of his goals went directly against Harry's. This meant that one of two things would have to happen for Harry to achieve his desires: either Voldemort would have to be neutralised, or Harry would have to find some way to make Voldemort go along with Harry's plans. In other words, they were stuck in an almost textbook version of the prisoner's dilemma.

The rational strategy in a non-iterated non-symmetric prisoner's dilemma was to defect if you could somehow ensure the other person would cooperate, and to cooperate otherwise. To do the former Harry would have to find some way of attack that Voldemort didn't expect and didn't prepare against, but that was also sufficiently powerful to take him out in one hit. That seemed…not likely. Furthermore, by extracting a vow of cooperation from Harry, Voldemort had effectively blocked him off from that strategy.

That left only cooperation, which meant finding some kind of leverage on Professor Quirrell sufficient enough to prevent him from defecting. That seemed unlikely… But probably less unlikely than defeating Voldemort in one hit.

Well, that made his goals clear enough - find leverage on Voldemort or find a way to kill him before he realises attack is coming. Harry opened his eyes. He wasted enough time thinking. Professor Quirrell was already frowning, though from the direction of his gaze he was examining a leaf colored in vivid shades of white, green, and purple.

There wasn't any obvious way to reach either of the goals, not yet. All Harry could do was ask the questions that seemed most likely to provide useful information, even if Harry didn't yet have a plan.

 _So we just ask about whatever seems most interesting?_ said Harry's Ravenclaw side. _I'm up for that._

 _Shut up,_ Harry told the voice; and then, on further reflection, decided that he was no longer pretending it was there.

Four topics came to Harry's mind as being priorities from the standpoint of curiosity about important things. Four questions, then, four major subjects, to try to fit in while this potion was still being brewed.

Four questions…

"I ask my first question," Harry said. "What really happened on the night of October 31st, 1981? Why was that night different from all other nights? I would like the entire story, please."

The question of how and why Lord Voldemort had survived his apparent death seemed likely to matter for future planning.

"I expected you would ask that," Professor Quirrell said, dropping a bellflower and a white glittering stone into the potion. "To begin, everything I told you about the horcrux spell is true; as you should realise, since I spoke in Parseltongue."

Harry nodded.

"Within seconds after you learned the details of the spell, you perceived the central flaw, and began pondering how the spell might be improved. Do you think the young Tom Riddle was any different?"

Harry shook his head.

"Well, he was," said Professor Quirrell. "Whenever I was tempted to despair of you, I reminded myself how I was an idiot at twice your age. When I was fifteen I made myself a horcrux as a certain book had shown me, using the death of Abigail Myrtle beneath the eyes of Slytherin's basilisk. I planned to make a new horcrux every year after I left Hogwarts, and call that my fallback plan if my other hopes of immortality did not come to fruition. In retrospect, the young Tom Riddle was grasping straws. The thought of making a _better_ horcrux, of not being content with the spell I had already learned... this thought did not come to me until I had grasped the stupidity of ordinary people, and realised which follies of theirs I had imitated. But in time I learned the habit that you inherited from me, to ask in every instance how it might be done better. To be content with the spell I had learned from a book, when it bore only a faint resemblance to what I truly wanted? Absurd! And so I set forth to create a better spell."

"You have true immortality, now?" Harry was perfectly aware that this was a question more important than war and strategy.

"Indeed," said Professor Quirrell. He paused in his Potions work and turned to face Harry fully; there was a look of exultation in the man's eyes that Harry had never seen there before. "In all the Darkest Arts I could find, in all the interdicted secrets to which Slytherin's Monster gave me keys, in all the lore remembered among wizardkind, I found only hints and smatterings of what I needed. So I rewove it and remade it, and devised a new ritual based on new principles. I kept that ritual burning in my mind for years, perfecting it in imagination, pondering its meaning and making fine adjustments, waiting for the intention to stabilise. At last I dared to invoke my ritual, an invented sacrificial ritual, based on a principle untested by all known magic. And I lived, and yet live." The Defense Professor spoke with quiet triumph, as though the act itself was so great that no words could ever do it justice. "I still use the word 'horcrux', but only from sentiment. It is a new thing entirely, the greatest of all my creations."

"As one of my questions you said you'd answer, I ask how to cast that spell," Harry said.

"Denied." The Defense Professor turned back to his potion, dropping in a gray-flecked white feather and a bellflower. "I had thought perhaps to teach you when you were older, for no Tom Riddle would be content otherwise; but I have changed my mind."

Memory is a hard thing to recall, sometimes, and Harry had been trying to remember if Professor Quirrell had dropped any hints about this subject before. Something about Professor Quirrell's phrasing sparked a memory: _Perhaps you will be told when you are older…_

"There are still physical anchors for your immortality," Harry said aloud. "It resembles the old horcrux spell by that much, which is another reason you still call them horcruxes." It was dangerous to say aloud, but Harry needed to _know._ "If I'm wrong, you can always deny it in Parseltongue."

Professor Quirrell was smiling evilly. " _Your guesss iss right, boy, for all the good it doess you._ "

Unfortunately, that wasn't a difficult vulnerability to cover if you were smart. Harry wouldn't ordinarily have made the suggestion, just in case the other person _hadn't_ thought of it for themselves. But in this case he'd already made it, and so it couldn't be traded for favors or used as an exploitable weakness. "One horcrux dropped into an active volcano, weighted so it would sink into the Earth's mantle," Harry said heavily. "The same place I thought of dropping the Dementor if I couldn't destroy it. And then you asked me where else I would hide something if I didn't want anyone to find it ever again. One horcrux buried kilometers down, in an anonymous cubic meter of the Earth's crust. One horcrux you dropped into the Mariana Trench. One horcrux floating high in the stratosphere, transparent. Even you don't know where they are, because you Obliviated the exact details from your memory. And the last horcrux is the Pioneer 11 plaque that you snuck into NASA and modified. It's where you get your image of the stars, when you cast the spell of starlight. Fire, earth, water, air, void." _Something of a riddle,_ the Defense Professor had called it, and therefore Harry had remembered it. Something of a Riddle.

"Indeed," said the Defense Professor. "It did give me something of a shock when you remembered it that quickly, but I suppose it makes no difference; all five are beyond my reach, or yours."

That might not be true, especially if there was some way to trace the magical connection somehow and determine the location... though presumably Voldemort would have done his best to obscure it... but what magic had done, magic might be able to defeat. Pioneer 11 might be far away by wizard standards, but NASA knew exactly where it was, and it was probably a lot more reachable if you could use magic to tell the Tsiolkovsky rocket equation to bugger off…

A sudden note of worry plucked at Harry's mind. There was no rule saying the Defense Professor needed to have told the truth about _which_ interstellar probe he'd horcruxed, and if Harry recalled correctly, communication and tracking of the Pioneer 10 probe had been lost shortly after the Jupiter fly-by.

Why wouldn't Professor Quirrell have just horcruxed them both?

The obvious next thought came to Harry. It was something that ought not to be suggested, if the other person had not yet thought of it. But it seemed extremely probable that Professor Quirrell had thought of it.

" _Tell me, teacher,_ " Harry hissed, " _would desstroying thosse five anchors sslay you?_ "

" _Why do you assk?_ " hissed the Defense Professor, with a lilt to the hiss that Parseltongue translated as snakish amusement. " _Do you ssusspect that ansswer is no?_ "

Harry couldn't think of how to answer, though he strongly suspected that it didn't matter in any case.

 _"Your ssusspicion iss right, boy. Desstroying thosse five would not render me mortal._ "

Harry's throat felt a bit dry again. If the spell had no disastrous cost associated with it... " _How many anchorss did you make?_ "

" _Would not ordinarily ssay, but iss clear you have already guesssed."_ The Defense Professor's smile widened. _"Ansswer iss that I do not know. Sstopped counting ssomewhere around one hundred and sseven. Ssimply made a habit of it each time I murdered ssomeone in private._ "

Over _one hundred_ murders, in private, before Lord Voldemort had stopped counting. And even worse news - "Your immortality spell still requires a human death? _Why?_ "

 _"Great creation maintainss life and magic within devicess created by ssacrificing life and magic of otherss._ " Again that hissing snake laughter. " _Liked falsse desscription of previousss horcrux sspell sso much, sso dissappointed when realissed truth of it, thoughtss of improved verssion came out in that sshape."_

Harry wasn't sure why the Defense Professor was giving him all this vital information, _but there had to be a reason,_ and that was making him nervous. "So you really are a disembodied spirit possessing Quirinus Quirrell."

" _Yess. I sshall return sswiftly, if thiss body iss killed. Will be greatly annoyed, and vengeful._ I am telling you this, boy, so that you do not try anything stupid."

"I understand," Harry said. He did his best to organize his thoughts, remember what he'd meant to ask next, while the Defense Professor turned his eyes back to the potion. The man's left hand was dribbling crushed seashell into the cauldron, while his right hand dropped in another bellflower. "So what did happen on October 31st? You... tried to turn the baby Harry Potter into a horcrux, either the new kind or the old kind. You did it deliberately, because you told Lily Potter," Harry took a breath. Now that he knew _why_ the chills were there, he could endure them. "Very well, I accept the bargain. Yourself to die, and the child to live. Now drop your wand so that I can murder you." In retrospect, it was clear that Harry had remembered that event mainly from Lord Voldemort's perspective, and only at the very end had he seen it through the baby Harry Potter's eyes. "What did you do? _Why_ did you do it?"

"Trelawney's prophecy," Professor Quirrell said. His hand tapped a bellflower with a strip of copper before dropping it in. "I spent long days pondering it, after Snape brought the prophecy to me. Prophecies are never trivial things. And how shall I put this in a way that does not make you think stupid things... well, I shall say it, and if you are stupid I shall be annoyed. I was fascinated by the prophecy's assertion that someone would be my equal, because it might mean that person could hold up the other end of an intelligent conversation. After fifty years of being surrounded by gibbering stupidity, I no longer cared whether my reaction might be considered a literary cliche. I was not about to pass up on that opportunity without thinking about it first. And then, you see, I had a _clever idea_." Professor Quirrell sighed. "It occurred to me how I might fulfill the Prophecy my own way, to my own benefit. I would mark the baby as my equal by casting the old horcrux spell in such fashion as to imprint my own spirit onto the baby's blank slate; it would be a purer copy of myself, since there would be no old self to mix with the new. In some years, when I had become bored with ruling Britain and moved on to other things, I would arrange with the other Tom Riddle that he should appear to vanquish me, and he would rule over the Britain he had saved. We would play the game against each other forever, keeping our lives interesting amid a world of fools. I knew a dramatist would predict that the two of us would end by destroying each other; but I pondered long upon it, and decided that both of us would simply decline to play out the drama. That was my decision and I was confident that it would remain so; both Tom Riddles, I thought, would be too intelligent to truly go down that road. The prophecy seemed to hint that if I destroyed all but a remnant of Harry Potter, then our spirits would not be so different, and we could exist in the same world."

"Something went wrong," Harry said. "Something that blew off the top of the Potters' home in Godric's Hollow, gave me the scar on my forehead, and left your burnt body behind."

Professor Quirrell nodded. His hands had slowed in their Potions work. "The resonance in our magic," Professor Quirrell said quietly. "When I had shaped the baby's spirit to be like my own..."

Harry remembered the moment in Azkaban when Professor Quirrell's Killing Curse had collided with his Patronus. The burning, tearing agony in his forehead, like his head had been about to split in half.

"I cannot count how many times I have thought of that night, rehearsing my mistake, thinking of wiser things I should have done," said Professor Quirrell. "I later decided that I should have thrown my wand from my hand and changed into my Animagus form. But that night... that night, I instinctively tried to control the chaotic fluctuations in my magic, even as I felt myself burning up from inside. That was the wrong decision, and I failed. So my body was destroyed, even as I overwrote the infant Harry Potter's mind; _either_ of us destroying all but a remnant of the other. And then..." Professor Quirrell's expression was controlled. "And then, when I regained consciousness inside my horcruxes, it turned out that my great creation did not work as I had hoped. I should have been able to float free of my horcruxes and possess any victim that consented to me, or that was too weak to refuse me. _That_ was the part of my great creation that failed my intent. As with the original horcrux spell, I would only be able to enter a victim who contacted the physical horcrux... and I had hidden my unnumbered horcruxes in places where nobody would ever find them. Your instinct is correct, boy, _this would not be a good time to laugh._ "

Harry stayed very quiet.

The Potions-making had come to a temporary pause, a space where no ingredients were added while the cauldron simmered for a time. "I spent most of my time looking at the stars," Professor Quirrell said, his voice quieter now. The Defense Professor had turned from the potion, staring at the white-illuminated walls of the room. "My remaining hope was the horcruxes I had hidden in the hopeless idiocy of my youth. Imbuing them into ancient lockets, instead of anonymous pebbles; guarding them beneath wells of poison in the center of a lake of Inferi, instead of portkeying them into the sea. If someone found one of those, and penetrated their ridiculous protections... but that seemed like a distant hope. I was not sure I would ever be embodied again. Yet at least I was immortal. The worst of all fates had been averted, my great creation had done that much. I had little left to hope for, and little left to fear. I decided that I would not go insane, since there seemed to be no advantage in it. Instead, I gazed out at the stars and thought, as the Sun slowly diminished behind me. I reflected on the errors of my past life; they were many, in that hindsight. In my imagination I constructed powerful new rituals I might attempt, if I was free to use my magic once more, and yet confident of my immortality. I contemplated ancient riddles at greater length than before, for all that I had once thought myself patient. I knew that if I won free, I would be more powerful by far than in my previous life; but I mostly did not expect that to happen." Professor Quirrell turned back to the potion. "Nine years and four months after that night, a wandering adventurer named Quirinus Quirrell won past the protections guarding one of my earliest horcruxes. The rest you know. And now, boy, you may say what we both know you are thinking."

"Um," Harry said. "It doesn't seem like a very smart thing to say -"

"Indeed, Mr. Potter. It is not a clever thing to say to me. Not even a little. Not in the slightest. But I _know you're thinking it,_ and you will _go on thinking it_ and I will _go on knowing that_ until you say it. So speak."

"So. Um. I realise that this is something that is more obvious in hindsight than in foresight, and I'm certainly not suggesting that you try to correct the error now, but if you are a Dark Lord and you happen to hear about a child who has been prophesied to defeat you, there is a certain spell which is unblockable, unstoppable, and works every single time on anything with a brain -"

" _Yes thank you Mr. Potter that thought occurred to me several times over the next nine years._ " Professor Quirrell picked up another bellflower and began crumbling it in his bare fist. "I made that principle the centerpiece of my Battle Magic curriculum after I learned its centrality the hard way. It was _not_ the first Rule on the younger Tom Riddle's list. It is only by harsh experience that we learn which principles take priority over which other principles; as mere words they all sound equally persuasive. In retrospect it would have been better if I had sent Bellatrix to the Potters' home in my place; but I had a Rule telling me that for such matters I must go myself and not try sending a trusted lieutenant. _Yes,_ I considered the Killing Curse; but I wondered if casting the Killing Curse at an infant would somehow cause the curse to bounce off and hit me, thus fulfilling the prophecy. How was I to know?"

"So use an axe, it's hard to get a prophecy-fulfilling spell backfire out of an axe," Harry said and then shut up.

"I decided the safest path was to try to fulfill the prophecy on my own terms," Professor Quirrell said. "Needless to say, the next time I hear a prophecy I do not like, I will tear it apart at _every possible point of intervention_ , rather than trying to play along." Professor Quirrell was crushing a rose as though to squeeze the juice out of it, still using his bare fist. "And now everyone thinks the Boy-Who-Lived is somehow immune to the Killing Curse, even though Killing Curses do not ruin houses or leave burnt bodies behind them, _because it has not occurred to them that Lord Voldemort would ever use any other spell._ "

Harry again stayed quiet. It had occurred to Harry that there was another obvious way that Lord Voldemort could have avoided his mistake. Something that might perhaps be easier to see given a Muggle upbringing, instead of the wizarding way of looking at things.

Harry had not yet decided whether to tell Professor Quirrell about his thought; there were both pros and cons to pointing out that particular error.

After a time Professor Quirrell picked up the next Potions ingredient, a strand of what looked like unicorn hair. "I tell you this as a caution," said Professor Quirrell. "Do not expect me to be delayed another nine years, if you somehow destroy this body of mine. I set horcruxes in better places at once, and now even that is unnecessary. Thanks to you, I learned where to find the Resurrection Stone. The Resurrection Stone does not bring back the dead, of course; but it holds a more ancient magic than my own for projecting the seeming of a spirit. And since I am one who has defeated death, Cadmus's Hallow acknowledged me its master, and answered all my will. I have now incorporated it into my great creation." Professor Quirrell smiled slightly. "I had many years earlier considered making that device a horcrux, but decided against it at the time, since I realized that the ring had magic of unknown nature... ah, such ironies does life play upon us. But I digress. _You_ , boy, you brought that about, you freed my spirit to fly where it pleases and seduce the most opportune victim, by being too casual with your secrets. It is a catastrophe for any who oppose me, and you wrought it with one finger drawing wetness on a tea-saucer. This world will be a safer place for all, if you learn the rectitude that wizardborns absorb in childhood. _And all thiss that I have jusst said iss the truth._ "

Harry closed his eyes, and his own hand massaged his forehead; if he had seen it from the outside, it would have looked the mirror of Professor Quirrell in deep thought.

Something about this story bothered Harry, but he couldn't tell what exactly. He put it aside for now. The problem of defeating Professor Quirrell was looking increasingly difficult, even by the standards of the sort of impossible problems that Harry had solved already. If communicating that difficulty was what Professor Quirrell was trying to do, he was _succeeding._ Well, this simply meant he could focus on finding leverage over Voldemort from now on. Perhaps he could offer to rule Britain as Voldemort's _nonhomicidal_ delegate? Professor Quirrell did not seem like the sort of person who enjoyed the minutia of government work, and having a good cop/bad cop pair should improve the efficiency of rulership quite a bit.

Harry stared at his hands, from where he had sat down upon the floor, feeling sadness shading over into despair. The Lord Voldemort who'd given Harry his dark side had spent _that long_ thinking things over and reflecting on his own thought processes... and had emerged as the calm, clear-headed, and still homicidal Professor Quirrell.

Perhaps it was to be expected. You didn't personally kill over a hundred people in cold blood over a _small_ error in the reasoning process.

Professor Quirrell added a pinch of golden hair to the _potion of effulgence,_ and that reminded Harry that time was continuing to move; the locks of bright hair were rarer than the bellflowers.

"I ask my second question," Harry said. "Tell me about the Philosopher's Stone. Does it do anything besides making Transfigurations permanent? Is it possible to make more Stones, and why is that problem hard?"

Professor Quirrell was bent over the potion, and Harry could not see his face. "Very well, I shall tell you the Stone's story as I have inferred it. The one and only power of the Stone is the imposition of permanency, to render a temporary form into a true and lasting substance - a power absolutely beyond ordinary spells. Conjurations such as the castle Hogwarts are maintained by a constant well of magic. Even Metamorphmagi cannot manifest golden fingernails and then trim them for sale. It is theorized that the Metamorphmagus curse merely rearranges the substance of their flesh, like a Muggle smith manipulates iron with hammer and tongs; and their body contains no gold. If Merlin himself could create gold from thin air, history does not record it. So the Stone, we can guess even before research, must be a very old thing indeed. In contrast, Nicholas Flamel has been known to the world for a mere six centuries. Tell me the obvious next question to ask, boy, if you wanted to trace the Stone's history."

"Um," Harry said. He rubbed his forehead, concentrating. If the Stone was old, but the world had only known Nicholas Flamel for six centuries... "Was there some other very long-lived wizard who disappeared at around the same time Nicholas Flamel showed up?"

"Close," said Professor Quirrell. "You recall that six centuries ago there was a Dark Lady called undying, the sorceress Baba Yaga? She was said to be able to heal any wound in herself, to change shape into any form she pleased... she held the Stone of Permanency, obviously. And then one year Baba Yaga agreed to teach Battle Magic at Hogwarts, under an old and respected truce." Professor Quirrell looked... _angry,_ a look such as Harry had rarely seen on him. "But she was not trusted, and so there was invoked a curse. Some curses are easier to cast when they bind yourself and others alike; Slytherin's Parselmouth curse is an example of such. In this case, Baba Yaga's signature, and signatures from every student and teacher of Hogwarts, were placed within an ancient device known as the Goblet of Fire. Baba Yaga swore not to shed a drop of students' blood, nor take from the students anything that was theirs. In return, the students swore not to shed a drop of Baba Yaga's blood, nor take from her anything that was hers. So they all signed, with the Goblet of Fire to witness it and punish the transgressor."

Professor Quirrell picked up a new ingredient, a loose thread of gold wrapped around a pinch of foul-looking substance. "Entering her sixth year at Hogwarts, then, was a witch named Perenelle. And although Perenelle was new-come into the beauty of her youth, her heart was already blacker than Baba Yaga's own -"

" _You're_ calling her evil?" Harry said, then realized he had just committed the fallacy of _ad hominem tu quoque._

"Hush, boy, I am telling the story. Where was I? Ah, yes, Perenelle, the beautiful and covetous. Perenelle seduced the Dark Lady over the months, with gentle touches and flirtations and the shy pretense of innocence. The Dark Lady's heart was captured, and they became lovers. And then one night Perenelle whispered how she had heard of Baba Yaga's shape-changing power and how this thought had enflamed her desires; thus Perenelle swayed Baba Yaga to come to her with the Stone in hand, to assume many guises in a single night, for their pleasures. Among other forms Perenelle bid Baba Yaga take the form of a man; and they lay together in the fashion of a man and a woman. But Perenelle had been a virgin until that night. And since they were all rather old-fashioned in those days, the Goblet of Fire accounted that as the shedding of Perenelle's blood, and the taking of what was hers; thus Baba Yaga was tricked into being forsworn, and the Goblet rendered her defenseless. Then Perenelle killed the unsuspecting Baba Yaga as she slept in Perenelle's bed, killed the Dark Lady who had loved her and come peacefully to Hogwarts under truce; and that was the end of the pact by which Dark Wizards and Witches taught Battle Magic at Hogwarts. For the next few centuries the Goblet of Fire was used to oversee pointless inter-school tournaments, and then it resided in a disused chamber at Beauxbatons, until I finally stole it." Professor Quirrell dropped a pale beige-pink twig into the cauldron, and its color changed to white just as it touched the surface. "But I digress. Perenelle took the Stone from Baba Yaga, and assumed the guise and name of Nicholas Flamel. She also kept her identity as Perenelle, calling herself Flamel's wife. The two have appeared together in public, but that might be done by any number of obvious methods."

"And the Stone's manufacture?" said Harry, his brain working to process all this. "I saw an alchemical recipe for it, in a book -"

"Another lie. Perenelle was making it appear as though 'Nicholas Flamel' had earned the right to live forever by completing a great magic that any could attempt. And she was giving others a false path to pursue, instead of seeking the one true Stone as Perenelle had sought Baba Yaga's." Professor Quirrell looked rather sour. "It should come as no surprise that I spent years trying to master that false recipe. Next you will ask why I did not kidnap, torture, and kill Perenelle after I learned the truth."

This had in fact been one of the questions that had come into Harry's mind.

Professor Quirrell continued to speak. "The answer is that Perenelle had foreseen and forestalled the ambitions of Dark Wizards like myself. 'Nicholas Flamel' publicly took Unbreakable Vows not to be coerced by any means into relinquishing his Stone - to guard immortality from the covetous, he claimed, as if that were a public service. I was afraid the Stone would be lost forever, if Perenelle died without saying where it was hidden, and her Vow prevented attempts at torture. Further, I had hopes of gaining Perenelle's knowledge, if I could find the right strategy to extract it from her. Though Perenelle began with little lore of her own, she has held hostage the lives of wizards greater than herself, holding out dribs and drabs of healing in exchange for secrets, and small reversals of age in exchange for power. Perenelle does not condescend to bestow any real youth upon others - but if you hear of a wizard who lived, greybearded, to the age of two hundred and fifty, you may be sure that her hand was in play. By my own generation, the centuries had given Perenelle enough of an advantage that she could raise up Albus Dumbledore as a counterweight to the Dark Lord Grindelwald. When I appeared as Lord Voldemort, Perenelle raised up Dumbledore yet further, parceling out another drop of her hoarded lore whenever Lord Voldemort seemed to gain an advantage. I felt like I ought to be able to figure out something clever to do with that situation, but I never did. "

Harry's wonderfully inventive brain jumped at this opportunity. "It seems like a fairly obvious scheme to me. If you had a secret trustworthy confederate that was also trusted by Dumbledore - Dumbledore's heir, in fact- you could have slowly leached out all her lore, by slowly ramping up your threat level. Either Flamel would teach Dumbledore who, in turn, would teach the lore to his heir, or you could kill Dumbledore and make the chain simpler. After she ran out of lore there would be no point in continuing this charade, and you could meet up with the confederate and share the acquired lore."

Professor Quirrell chuckled, "Are you trying to make you seem useful to keep around, boy?"

Harry forced himself to grin. "Yes. Is it working?"

Professor Quirrell chuckled, "Perhaps. The idea seems obvious in retrospect, though before now arranging for such a heir would not have been feasible. It matters little now. Where was I? I did not attack her directly, for I was not sure of my great creation; it was not impossible that I would someday need to go begging to her for a dollop of reversed age." Professor Quirrell dropped two bellflowers at once into the potion, and they seemed to merge as they touched the bubbling liquid. "But now I am sure of my creation, and so I have decided that the time has come to take the Stone by force."

Harry hesitated. "I would like to hear you answer in Parseltongue, was all of that true?"

" _None of it iss known to me to be falsse,_ " said Professor Quirrell. "Telling a tale implies filling in certain gaps; I was not present to observe when Perenelle seduced Baba Yaga. _The bassicss sshould be mosstly correct, I think._ "

Harry had noticed a trace of confusion _._ "Then I don't understand why the Stone is here in Hogwarts. Wouldn't the best defense just be hiding it under an anonymous rock in Greenland?"

"Perhaps she respected my abilities as a particularly good finder," said the Defense Professor. He appeared focused on his cauldron as he dipped a bellflower into a jar of liquid labeled with the Potions symbol for rainwater.

 _We are very much alike, the Defense Professor and I, in some ways if not others. If I imagine what I'd do, given his problem…_

"Did you bluff everyone into _believing_ you had some way of finding the Stone?" Harry said aloud. "So that Perenelle would put it inside Hogwarts, where Dumbledore could guard it?"

The Defense Professor sighed, not looking up from the cauldron. "I suppose that strategem would be futile to conceal from you. Yes, after I possessed Quirrell and returned, I implemented a strategy I had conceived while gazing at the stars. First I made sure to be accepted as Defense Professor at Hogwarts, for it would not do to have suspicions raised while I was still seeking employment. When that was done, I arranged for one of Perenelle's curse-breaking expeditions to discover a falsified but credible inscription describing how the Crown of the Serpent could be used to seek out the Stone wherever it was hidden. Immediately after, before Perenelle could buy up the Crown, it was stolen; furthermore I left clear indications that the thief had possessed the power to speak to snakes. So Perenelle thought that I could infallibly find the Stone's location, and that it needed a guardian powerful enough to defeat me. That is how the Stone came to be held in Hogwarts, in Dumbledore's domain. Just as I intended, naturally, since I had already gained access to Hogwarts for the year. I think that is all of this that concerns you, if I speak not of future plans."

Harry frowned. Professor Quirrell should not have told him that. Unless the strategy had somehow become irrelevant to any future deception of Perenelle...? Or unless, by answering so quickly, the Defense Professor had hoped to have people conclude that it was a double-bluff, and that the Crown of the Serpent really could find the Stone…

Harry decided not to question this answer in Parseltongue.

Another lock of bright hair, seeming white but not with age, was gently dribbled into the cauldron, again reminding Harry that they were on a time limit. Harry considered, but he couldn't see any further path to pursue this line of questioning; there was no known way to manufacture more Philosopher's Stones and no obvious way to invent such, which was probably the _objectively_ worst news Harry had heard all day.

Harry took a deep breath. "I ask my third question," Harry said. "What was your objective during the Wizarding War?" Harry said. "I mean, what -" His voice wobbled. "What was the _point_ of the _entire thing?_ " His brain repeating endlessly, _Why, why, why Lord Voldemort…_

Professor Quirrell lifted an eyebrow. "They told you about David Monroe, did they not?"

"Yes. You were both David Monroe and Lord Voldemort during the Wizarding War, I understood that part. You killed David Monroe, disguised yourself as him, and wiped out David Monroe's family so they wouldn't notice any differences -"

"Indeed."

"You planned to control whichever side won the Wizarding War, regardless of which side won. But why did one side have to be _Voldemort?_ I, I mean, wouldn't it have been easier to gain public support with someone less... with someone less Voldemort?"

Professor Quirrell's mallet made an unusually loud _thud_ as it crushed white butterfly wings, mixing them with another bellflower. "I _planned,_ " Professor Quirrell said harshly, "for Lord Voldemort to _lose_ to David Monroe. The flaw in that strategy was the absolute wretchedness of -" Professor Quirrell stopped. "No, I am telling the tale out of order. Listen, boy, when I had devised my great creation and come into the fullness of my magic, I thought the time had come for me to take political power into my hands. It would be inconvenient, certainly, and take up my time in ways that were not enjoyable. But I knew the Muggles would eventually destroy the world or make war on wizardkind or both, and something had to be done if I was not to wander a dead or dull world through my eternity. Having attained immortality I needed a new ambition to occupy my decades, and to prevent the Muggles from ruining everything seemed a goal of acceptable scope and difficulty. It is a source of continual amusement to me that I, of all people, am the only one really taking action towards that end. Though I suppose it would make sense for the mortal insects not to care about their world's end; why should they, when they are just going to die regardless, and can save themselves the inconvenience of trying to do anything difficult along the way? But I digress. I saw how Dumbledore had risen to power from his defeat of Grindelwald, so I thought I would do the same. I had long ago taken my vengeance on David Monroe - he was an annoyance from my year in Slytherin - so I bethought to also steal his identity, and wipe out his family to make myself heir of his House. And I conceived also a great foe for David Monroe to fight, the most terrifying Dark Lord imaginable, clever beyond reckoning; more dangerous by far than Grindelwald, for his intelligence would be perfected in all the ways that Grindelwald had been flawed and self-destructive. A Dark Lord who would do his cunning utmost to disrupt the alliances who would fight him, a Dark Lord who would command the deepest loyalty from his followers through his oratical skills. The most dreadful Dark Lord who had ever threatened Britain or the world, that was who David Monroe would defeat."

Professor Quirrell's mallet struck a bellflower and then a different pale flower with two more thuds. "But then, while I had sometimes played the part of Dark Wizard in my wanderings, I had never adopted the identity of a full-fledged Dark Lord with underlings and a political agenda. I had no practice at the task, and I was mindful of the story of Dark Evangel and the disaster of her first public appearance. According to what she said afterward, she had meant to call herself the Walking Catastrophe and the Apostle of Darkness, but in the excitement of the moment she introduced herself as the Apostrophe of Darkness instead. After that she had to ruin two entire villages before anyone took her seriously."

"So you decided to try a small-scale experiment first," Harry said. A sickness rose up in him, because in that moment Harry _understood,_ he saw himself reflected; the next step was just what Harry himself would have done, if he'd had no trace of ethics whatsoever, if he'd been that empty inside. "You created a disposable identity, to learn how the ropes worked, and get your mistakes out of the way."

"Indeed. Before becoming a truly terrible Dark Lord for David Monroe to fight, I first created for practice the persona of a Dark Lord with glowing red eyes, pointlessly cruel to his underlings, pursuing a political agenda of naked personal ambition combined with blood purism as argued by drunks in Knockturn Alley. My first underlings were hired in a tavern, given cloaks and skull masks, and told to introduce themselves as Death Eaters."

The sick sense of understanding deepened, in the pit of Harry's stomach. "And you called yourself Voldemort."

"Just so, General Chaos." Professor Quirrell was grinning, from where he stood by the cauldron. "I wanted it to be an anagram of my name, but that would only have worked if I'd conveniently been given the middle name of 'Marvolo', and then it would have been a stretch. Our actual middle name is Morfin, if you're curious. But I digress. I thought Voldemort's career would last only a few months, a year at the longest, before the Aurors brought down his underlings and the disposable Dark Lord vanished. As you perceive, I had vastly overestimated my competition. And I could not _quite_ bring myself to torture my underlings when they brought me bad news, no matter what Dark Lords did in plays. I could not _quite_ manage to argue the tenets of blood purism as incoherently as if I were a drunk in Knockturn Alley. I was not trying to be clever when I sent my underlings on their missions, but neither did I give them entirely pointless orders -" Professor Quirrell gave a rueful grin that, in another context, might have been called charming. "One month after that, Bellatrix Black prostrated herself before me, and after three months Lucius Malfoy was negotiating with me over glasses of expensive Firewhiskey. I sighed, gave up all hope for wizardkind, and began as David Monroe to oppose this fearsome Lord Voldemort."

"And then what happened -"

A snarl contorted Professor Quirrell's face. "The absolute inadequacy of every single institution in the civilization of magical Britain is what happened! You cannot comprehend it, boy! I cannot comprehend it! It has to be seen and even then it cannot be believed! You will have observed, perhaps, that of your fellow students who speak of their family's occupations, three in four seem to mention jobs in some part or another of the Ministry. You will wonder how a country can manage to employ three of its four citizens in bureaucracy. The answer is that if they did not all prevent each other from doing their jobs, none of them would have any work left to do! The Aurors were competent as individual fighters, they did fight Dark Wizards and only the best survived to train new recruits, but their leadership was in absolute disarray. The Ministry was so busy routing papers that the country had _no_ effective opposition to Voldemort's attacks except myself, Dumbledore, and a handful of untrained irregulars. A shiftless, incompetent, cowardly layabout, Mundungus Fletcher, was considered a key asset in the Order of the Phoenix - because, being otherwise unemployed, he did not need to juggle another job! I tried weakening Voldemort's attacks, to see if it was _possible_ for him to lose; at once the Ministry committed fewer Aurors to oppose me! I had read Mao's Little Red Book, I had trained my Death Eaters in guerilla tactics - for nothing! For nothing! I was attacking all of magical Britain and in every engagement my forces _outnumbered_ their opposition! In desperation, I ordered my Death Eaters to systematically assassinate every single incompetent managing the Department of Magical Law Enforcement. One paper-pusher after another volunteered to accept higher positions despite the fate of their predecessors, gleefully rubbing their hands at the prospect of promotion. Every one of them thought they would cut a deal with Lord Voldemort on the side. It took _seven months_ to murder our way through them all, and not a single Death Eater asked why we were bothering. And then, even with Bartemius Crouch risen to Director and Amelia Bones as Head Auror, it was still too little. I could have done better fighting _alone._ Dumbledore's aid was not worth his moral restraints, and Crouch's aid was not worth his respect for the law." Professor Quirrell turned up the fire beneath the potion.

"And eventually," Harry said through the heart-sickness, "you realized you were just having more fun as Voldemort."

"It is the least annoying role I have ever played. If Lord Voldemort says that something is to be done, people _obey him_ and _do not argue._ I did not have to suppress my impulse to Cruciate people being idiots; for once it was all part of the role. If someone was making the game less pleasant for me, I just said _Avadakedavra_ regardless of whether that was strategically wise, and they never bothered me again." Professor Quirrell casually chopped a small worm into bits. "But my true epiphany came on a certain day when David Monroe was trying to get an entry permit for an Asian instructor in combat tactics, and a Ministry clerk denied it, smiling smugly. I asked the Ministry clerk if he understood that this measure was meant to _save his life_ and the Ministry clerk only smiled more. Then in fury I threw aside masks and caution, I used my Legilimency, I dipped my fingers into the cesspit of his stupidity and _tore_ out the truth from his mind. I did not understand and I _wanted to understand._ With my command of Legilimency I forced his tiny clerk-brain to live out alternatives, seeing what his clerk-brain would think of Lucius Malfoy, or Lord Voldemort, or Dumbledore standing in my place." Professor Quirrell's hands had slowed, as he delicately peeled bits and small strips from a chunk of candle-wax. "What I finally realized that day is complicated, boy, which is why I did not understand it earlier in life. To you I shall try to describe it anyway. Today I know that Dumbledore does not stand at the top of the world, for all that he is the Supreme Mugwump of the International Confederation. People speak ill of Dumbledore openly, they criticize him proudly and to his face, in a way they would not dare stand up to Lucius Malfoy. _You_ have acted disrespectfully toward Dumbledore, boy, do you know why you did so?"

"I'm... not sure," Harry said. Having Tom Riddle's leftover neural patterns was certainly an obvious hypothesis.

"Wolves, dogs, even chickens, fight for dominance among themselves. What I finally understood, from that clerk's mind, was that to him Lucius Malfoy had dominance, Lord Voldemort had dominance, and David Monroe and Albus Dumbledore did not. By taking the side of good, by professing to abide in the light, we had made ourselves _unthreatening._ In Britain, Lucius Malfoy has dominance, for he can call in your loans, or send Ministry bureaucrats against your shop, or crucify you in the _Daily Prophet,_ if you go openly against his will. And the most powerful wizard in the world has no dominance, because everyone knows that he is," Professor Quirrell's lips curled, " _a hero out of stories,_ relentlessly self-effacing and too humble for vengeance. Tell me, child, have you ever seen a drama where the hero, before he consents to save his country, demands so much gold as a barrister might receive for a court case?"

"Actually there have been a _lot_ of heroes like that in Muggle fiction, I'll name Han Solo just to start-"

"Well, in magical drama it is not so. It is all humble heroes like Dumbledore. It is the fantasy of the powerful _slave_ who will never truly rise above you, never demand your respect, never even ask you for pay. Do you understand now?"

"I... think so," Harry said. Frodo and Samwise from _Lord of the Rings_ did seem to match the archetype of a completely non-threatening hero. "You're saying that's how people think of Dumbledore? I don't believe the Hogwarts students see him as a hobbit."

"In Hogwarts, Dumbledore does punish certain transgressions against his will, so he is feared to some degree - though the students still make free to mock him in more than whispers. Outside this castle, Dumbledore is sneered at; they began to call him mad, and he aped the part like a fool. Step into the role of a savior out of plays, and people see you as a slave to whose services they are entitled and whom it is their enjoyment to criticize; for it is the privilege of masters to sit back and call forth helpful corrections while the slaves labor. Only in the tales of the ancient Greeks, from when men were less sophisticated in their delusions, may you see the hero who is also high. Hector, Aeneas, those were heroes who retained their right of vengeance upon those who insulted them, who could demand gold and jewels in payment for their services without sparking indignation. And if Lord Voldemort conquered Britain, he might then condescend to show himself noble in victory; and nobody would take his goodwill for granted, nor chirp corrections at him if his work was not to their liking. When he won, he would have _true_ respect. I understood that day in the Ministry that by envying Dumbledore, I had shown myself as deluded as Dumbledore himself. I understood that I had been trying for the wrong place all along. You should know this to be true, boy, for you have made freer to speak ill of Dumbledore than you ever dared speak ill of me. Even in your own thoughts, I wager, for instinct runs deep. You knew that it might be to your cost to mock the strong and vengeful Professor Quirrell, but that there was no cost in disrespecting the weak and harmless Dumbledore."

"Thank you," Harry said through the pain, "for that valuable lesson, Professor Quirrell, I see that you are right about what my mind was doing." Though Tom Riddle's memories had probably also had something to do with the way he had sometimes lashed out at Dumbledore for no good reason, Harry hadn't been like that around Professor McGonagall... who admittedly had the power to deduct House Points and didn't have Dumbledore's air of tolerance... no, it was still true, Harry would have been more respectful even in his own thoughts if Dumbledore had not seemed _safe_ to disrespect.

So that had been David Monroe, and that had been Lord Voldemort…

It still hadn't answered the most puzzling question, and Harry wasn't sure that asking it would be wise. If, somehow, Lord Voldemort had managed _not to think of it,_ and then Professor Quirrell had still managed not to think of it during nine years of contemplation, then it wasn't wise to say... or maybe it was; the agonies of the Wizarding War had not been good for Britain.

Harry decided, and spoke. "One thing that did confuse me was why the Wizarding War lasted so long," Harry ventured. "I mean, maybe I'm underestimating the difficulties that were facing Lord Voldemort-"

"You want to know why I did not Imperius some of the stronger wizards who could Imperius others, slay the very strongest wizards who could have resisted my Imperius, and take over the Ministry in, oh, perhaps three days."

Harry nodded, "Pretty much."

Professor Quirrell looked contemplative; his hand was sifting grass clippings into the cauldron, bit by bit. That ingredient, if Harry remembered correctly, was something like four-fifths towards the end of the recipe.

"I wondered that myself," the Defense Professor said finally, "when I heard Trelawney's prophecy from Snape, and I contemplated the past as well as the future. If you had asked my past self why he did not use the Imperius, he would have spoken of the need to be _seen_ to rule, to openly command the Ministry bureaucracy, before it was time to turn his eyes outward to other countries. He would have remarked on how a quick and silent victory might bring challenges later. He would have remarked on the obstacle presented by Dumbledore and his incredible defensive prowess. And he would have had similar excuses for every other quick path he considered. Somehow it was never the right time to bring my plans to their final phase, there was always one more thing to do first. Then I heard the prophecy and I _knew_ that it was time, for Time itself was taking notice of me. That the span for hesitation was done. And I looked back, and realised somehow this had been going on for years. I think..." The occasional bit of grass was still dropping down from his hand, but Professor Quirrell did not seem to pay it any mind. "I thought, when I was contemplating my past beneath the starlight, that I had become too accustomed to playing against Dumbledore. Dumbledore was intelligent, he tried diligently to be cunning, he did not wait for me to strike but presented me with surprises. He made bizarre moves that played out in fascinating and unpredictable ways. In retrospect, there were many obvious plans for destroying Dumbledore; but I think some part of me did not want to go back to playing solitaire instead of chess. It was when I had the prospect of creating another Tom Riddle to plot against, someone even more worthy than Dumbledore, that I was first willing to contemplate the end of my war. Yes, in retrospect that sounds stupid, but sometimes our emotions are more foolish than we can bring our reason to admit. I would never have espoused such a policy deliberately. It would have violated Rules Nine, Sixteen, Twenty, and Twenty-two and that is too much even if you are enjoying yourself. But to repeatedly decide that there was one more thing left to be done, one more advantage left to be gained, one more piece that I simply _had_ to move into place, before abandoning an enjoyable time in my life and moving on to the more tedious rulership of Britain... well, even I am not immune to a mistake like that, if I do not realize that I am making it."

And that was when Harry knew what was going to happen at the end of this, after the Philosopher's Stone had been retrieved.

At the end of this, Professor Quirrell was going to kill him.

Professor Quirrell didn't want to kill him. It was possible that Harry was the only person in the world against whom Professor Quirrell _wouldn't_ be able to use a Killing Curse. But Professor Quirrell thought he had to do it, for whatever reason.

That was why Professor Quirrell had decided that it was necessary to brew the _potion of effulgence_ the long way. That was why Professor Quirrell had been so easily negotiated into answering these questions, into finally talking about his life with someone who might understand. Just like Lord Voldemort had delayed the end of the Wizarding War to play longer against Dumbledore.

There was no particular shock to the realization, just an increased sense of urgency; some part of Harry had already known this, and had simply been waiting for an excuse to make it known to deliberation. There had been too many things said here that Professor Quirrell would not reveal to anyone with an expected lifespan measured in more than hours. The overwhelming isolation and loneliness of the life Professor Quirrell had described might explain why he was willing to violate his Rules and talk with Harry, _given_ that Harry was going to die soon and that the world did not actually work like a play where the villain disclosing his plans would always fail to kill the hero afterward. But Harry's death certainly had to be in those future plans somewhere.

It wouldn't happen immediately after they took the stone out of the mirror; Professor Quirrell swore to not kill Harry directly, so he was safe enough for now at least. He still had time to come up with a way out of this.

Harry now had to reconsider his plans, taking Voldemort's desire to kill him into account.

There weren't any obvious reasons to kill Harry - he did not possess magic capable of harming Professor Quirrell, and based on Quirrell's description of the events of that fateful October night he actually _wanted_ a competent, intelligent opponent. This meant that Professor Quirrell knew something that Harry didn't, and that something made Harry an actual threat to Voldemort's well-being. At the moment, Harry's mind was drawing a blank in regards to what that might be. He briefly considered asking why Professor Quirrell wanted to kill him, but decided against it. If Quirrell still haven't revealed the reason for it, he clearly did not intend for Harry to know.

A pinch of red-brown dust was gently sifted into the potions cauldron, and Harry asked his fourth and final question, the one that had seemed to have the lowest priority, but still mattered. "What's the truth behind this entire school year? All the plots you ran, all the plots you know about."

"Hm," said Professor Quirrell, dropping another bellflower into the potion, accompanied by a plant-shape like a tiny cross. "Let me see... the most shocking twist is that the Defense Professor turns out to be secretly Voldemort."

"Well, obviously," Harry said, with a good deal of self-directed bitterness.

"Then where do you wish me to start?"

"Why did you kill Hermione?" The question just slipped out.

Professor Quirrell's pale eyes glanced up from the potion, watched him intently. "One would think that should be evident - but I suppose I cannot blame you for distrusting what seems evident. To understand the object of an obscure plot, observe its consequences and ask who might have intended them. I killed Miss Granger to improve your position relative to that of Lucius Malfoy, since my plans did not call for him to have so much leverage over you. I admit I am impressed by how far you managed to parlay that opening."

Harry unclenched his teeth, which took an effort. "That's after your failed attempt to _frame_ Hermione for the attempted murder of Draco and _send her to Azkaban_ because of _why?_ Because you didn't like the influence she was having on me?"

"Don't be ridiculous," Professor Quirrell said. "If I had only wished to remove Miss Granger, I would not have brought the Malfoys into it. I observed your game with Draco Malfoy and found it amusing, but I knew it could not continue for very long before Lucius learned and intervened; and then your folly would have brought you great trouble, for Lucius would not take it lightly. Had you just been able to _lose_ during the Wizengamot trial, _lose_ as I had taught you, then in only two more weeks, ironclad evidence would have shown that Lucius Malfoy, after discovering his son's seeming perfidy, had Imperiused Professor Sprout into using the Blood-Cooling Charm on Mr. Malfoy and casting the False Memory Charm on Miss Granger. Lucius would have been swept off the political gameboard, sent to exile if not Azkaban; Draco Malfoy would have inherited the wealth of House Malfoy, and your influence over him would have been unchallenged. Instead I had to abort that plot in mid-course. You managed to completely disrupt the real plan in the course of sacrificing double your entire fortune, by giving Lucius Malfoy the perfect opportunity to prove his true concern for his son. You have an incredible anti-talent for meddling, I must say."

"And you also thought," Harry said, even with his dark side's patterns he had to work to keep his voice level and cool, "that two weeks in Azkaban would improve Miss Granger's disposition, and get her to stop being a bad influence on me. So you somehow arranged for there to be newspaper stories calling for her to be sent to Azkaban, rather than some other penalty."

Professor Quirrell's lips drew up in a thin smile. "Good catch, boy. Yes, I thought she might serve as your Bellatrix. That particular outcome would also have provided you with a constant reminder of how much respect was due the law, and helped you develop appropriate attitudes toward the Ministry."

"Your plot was stupidly complicated and had no chance of working." Harry knew he ought to be more tactful, that he was engaging in more of what Professor Quirrell called _folly,_ but in that instant he could not bring himself to care.

"It was less complicated than Dumbledore's plot to have the three armies tie in the Christmas Battle, and not much more complicated than my own plot to make you think Dumbledore had blackmailed Mr. Zabini. The insight you are missing, Mr. Potter, is that these were not plots that _needed_ to succeed." Professor Quirrell continued to casually stir the potion, smiling. "There are plots that _must_ succeed, where you keep the core idea as simple as possible and take every precaution. There are also plots where it is acceptable to fail, and with those you can indulge yourself, or test the limits of your ability to handle complications. It was not as if something going wrong with any of those plots would have killed me." Professor Quirrell was no longer smiling. "Our journey into Azkaban was of the first type, and I was less amused by your antics there."

"What _exactly_ did you do to Hermione?" Some part of Harry wondered at the evenness of his voice.

"Obliviations and False Memory Charms. I could not trust anything else to go undetected by the Hogwarts wards and the scrutiny I knew her mind would undergo." A flicker of frustration crossed Professor Quirrell's face. "Part of what you rightly call complication is because the first version of my plot did not go as planned, and I had to modify it. I came to Miss Granger in the hallways wearing the appearance of Professor Sprout, to offer her a conspiracy. My first attempt at suasion failed. I Obliviated her and tried again with a new presentation. The second bait failed. The third bait failed. The _tenth_ bait failed. I was so frustrated that I began going through my entire library of guises, including those more appropriate to Mr. Zabini. _Still_ nothing worked. The child _would not_ violate her childish code."

" _You_ do not get to call her childish, Professor." Harry's voice sounded strange in his own ears. "Her code _worked._ It prevented you from tricking her. The whole point of having deontological ethical injunctions is that arguments for violating them are often much less trustworthy than they look. You don't get to criticize her rules when they worked exactly as intended." After they resurrected Hermione, Harry would tell her that Lord Voldemort himself hadn't been able to tempt her into doing wrong, and that was why he'd killed her.

"Fair enough, I suppose," said Professor Quirrell. "There is a saying that even a stopped clock is right twice a day, and I do not think Miss Granger was actually being reasonable. Still, Rule Ten: one must not rant about the opposition's unworthiness after they have foiled you. Regardless. After two full hours of failed attempts, I realized that I was being over-stubborn, and that I did not need Miss Granger to carry out the exact part I had planned for her. I gave up on my original intent, and instead imbued Miss Granger with False Memories of watching Mr. Malfoy plotting against her under circumstances that implied she should not tell you or the authorities. In the end it was Mr. Malfoy who gave me the opening I needed, entirely by luck." Professor Quirrell dropped a bellflower and a scrap of parchment into the cauldron.

"Why did the wards show the Defense Professor as having killed Hermione?"

"I wore the mountain troll as a false tooth while Dumbledore was identifying me to the Hogwarts wards as the Defense Professor." A slight smile. "Other living weapons cannot be Transfigured; they will not survive the disenchantment for the requisite six hours to avoid being traced by Time-Turner. The fact that a mountain troll was used as a weapon of assassination was a clear sign that the assassin had needed a proxy weapon that could be Transfigured safely. Combined with the evidence of the wards, and Dumbledore's own knowledge of how he had identified me to Hogwarts, you could have deduced who was responsible - in theory. However, experience has taught me that such puzzles are far harder to solve when you do not already know the solution, and I considered it a small risk. Ah, that reminds me, I have a question of my own." The Defense Professor was now giving Harry an intent look. "What gave me away at the last, in the corridor outside these chambers?"

Harry put aside other emotions to weigh up the cost and benefit of answering honestly, came to the conclusion that the Defense Professor was giving away far more information than he was getting ( _why?_ ) and that it was best not to give the appearance of reticence. "The main thing," Harry said, "was that it was too improbable that everyone had arrived in Dumbledore's corridor at the same time. I tried running with the hypothesis that everyone who arrived had to be coordinated, including you."

"But I had said that I was following Snape," the Defense Professor said. "Was that not plausible?"

"It was, but..." Harry said. "Um. The laws governing what constitutes a good explanation don't talk about plausible excuses you hear afterward. They talk about the probabilities we assign in advance. That's why science makes people do advance predictions, instead of trusting explanations people come up with afterward. And I wouldn't have predicted in advance for you to follow Snape and show up like that. Even if I'd known in advance that you could put a trace on Snape's wand, I wouldn't have _expected_ you to do it and follow him just then. Since your explanation didn't make me feel like I would have predicted the outcome in advance, it remained an improbability. I started to wonder if Sprout's mastermind might have arranged for you to show up, too. And then I realised the note to myself hadn't really come from future-me, and that gave it away completely."

"Ah," said the Defense Professor, and sighed. "Well, I think it is all working out for the best. You did understand only too late; and there would have been inconveniences as well as benefits to you remaining unaware."

"What on _Earth_ were you trying to do? The reason I was trying so hard to figure it out was that the whole thing was just so weird."

"That should have pointed at Dumbledore, not myself," said Professor Quirrell, and frowned. "The fact is that Miss Greengrass was not supposed to arrive in that corridor for several hours... though I suppose, since I did have Mr. Malfoy give her the clue I assigned her, it is not too surprising they banded together. Had Mr. Nott arrived seemingly alone, events would have played out less farcically. But I consider myself a specialist in battlefield control magics, and I was able to ensure that the fight went as I wished. I suppose it did end up looking a bit ridiculous." The Defense Professor dropped a peach slice and a bellflower into the cauldron. "But let us defer our discussion of the Mirror until we reach it. Did you have any more questions concerning Miss Granger's regrettable and hopefully temporary demise?"

"Yes," Harry said in an even voice. "What did you do to the Weasley twins? Dumbledore thought - I mean, the school saw the Headmaster go to the Weasley twins after Hermione was arrested. Dumbledore thought you, as Voldemort, had wondered why Dumbledore had done so, and that you'd checked on the Weasley twins, found and took their map, and Obliviated them afterward?"

"Dumbledore was quite correct," Professor Quirrell said, shaking his head as though in wonderment. "He was also an utter fool to leave the Hogwarts Map in the possession of those two idiots. I had an unpleasant shock after I recovered the Map; it showed my name and yours correctly! The Weasley idiots had thought it a mere malfunction, especially after you received your Cloak and your Time-Turner. If Dumbledore had kept the Map himself - if the Weasleys had ever spoken of it to Dumbledore - but they did not, thankfully."

 _Showed my name and yours correctly -_

"I would like to see that," Harry said.

Without taking his eyes from the cauldron, Professor Quirrell drew a folded parchment from within his robes, hissed at it _"Sshow our ssurroundingss_ ", and tossed the folded parchment toward Harry. It cut unerringly through the air, an increase of doom breathing on Harry's senses as it moved toward him, and then it fluttered gently to Harry's feet.

Harry picked up the parchment and unfolded it.

At first the parchment seemed blank. Then, as though an unseen pen were moving across it, the outline of walls and doors appeared, all drawn in handwritten lines. The writing outlined a series of chambers, most of them shown as empty; the last chamber in the series had a confused scribble in its center, as though the Map were trying to indicate its own bewilderment; and the second-to-last chamber showed two names within, written in positions within the chamber corresponding to where Harry was sitting and Professor Quirrell was standing.

 _Tom M. Riddle._

 _Tom M. Riddle._

Harry gazed at the parchment, an unpleasant chill coming over him. It was one thing to hear Lord Voldemort claim that your name was Tom Riddle; it was another thing to find that Hogwarts's magic agreed. " _Did you tamper with thiss map to achieve thiss ressult, or did it appear before you by ssurprisse?"_

 _"Wass ssurprisse,_ " replied Professor Quirrell, with an overtone of hissing laughter. " _No trickss._ "

Harry folded the Map and threw it back in Professor Quirrell's direction; some force caught it in midair before it reached the floor, and drew the Map back into Professor Quirrell's robes.

The Defense Professor spoke. "I should also like to volunteer that Snape was guiding Miss Granger and her underlings toward bullies, and sometimes intervening to protect them."

"I knew that."

"Interesting," said Professor Quirrell. "Did Dumbledore also learn of this? Answer in Parseltongue."

" _Not sso far ass I know,_ " hissed Harry.

"Fascinating," said Professor Quirrell. "You may be interested to know this as well: _Potionss-maker had to work in ssecret because hiss plot oppossed sschoolmasster's plot._ "

Harry thought about this, while Professor Quirrell blew on the potion as though to cool it, though the fire still burned under the cauldron; then added a pinch of dirt and a drop of water and a bellflower. "Please explain," Harry said.

"Has it never occurred to you to wonder why Dumbledore chose Severus Snape as the Head of House Slytherin? To say that it was a cover for his work as Dumbledore's spy explains nothing. Snape could have been a Potions Master only, and not the Head of Slytherin at all. Snape could have been made Keeper of Grounds and Keys, if he needed to stay within Hogwarts! Why the _Head of House Slytherin?_ Surely it occurred to you that this could not have good effects upon the Slytherins, according to Dumbledore's moral pretenses?"

The thought hadn't occurred to Harry in _exactly_ those terms, no... "I wondered something like it. I didn't put the dilemma in that precise form."

"And now that you have, is the solution obvious?"

"No," Harry said.

"Disappointing. You have not learned enough cynicism, you have not grasped the _flexibility_ of what moralists call morality. To fathom a plot, look at the consequences and ask if they might be intended. Dumbledore was deliberately sabotaging Slytherin House - don't give me that look, boy, _I am sspeaking truth._ During the last Wizarding War, Slytherins filled out my ranks of underlings, and other Slytherins in the Wizengamot supported me. Look at it from Dumbledore's perspective, and remember that he has no native understanding of Slytherin's ways. Think of Dumbledore becoming increasingly sad over this Hogwarts House that seems the source of so much ill-doing. And then behold, Dumbledore puts in as Head of Slytherin the person of Snape. Snape! Severus Snape! A man who would teach his House neither cunning nor ambition, a man who would impose lax discipline and make its children weak! A man who would offend students of other Houses, who would ruin Slytherin's name among them! A man whose surname was unknown in magical Britain and certainly not noble, who went about half in rags! Do you think Dumbledore ignorant of the consequence? When Dumbledore was the one who brought it about, and had motive to bring it about? I expect Dumbledore told himself that more lives would be saved during the next Wizarding War if Voldemort's future Death Eaters were weakened." Professor Quirrell dropped into the cauldron a chip of ice, slowly melting as it touched the surface froth. "Continue the process long enough, and no child would want to go to Slytherin. The House would be retired, and if the Hat kept calling the name, it would become a mark of ignominy among children who would afterward be distributed among the other three Houses. From that day on, Hogwarts would have three upstanding Houses of courage and scholarship and industry, with no House of Bad Children added to the mix; just as if the three Founders of Hogwarts had been wise enough in the beginning to refuse Salazar Slytherin their company. That, I expect, was Dumbledore's intended end-game; a short-term sacrifice for the greater good." Professor Quirrell smiled sardonically. "And Lucius let it all happen without protest or even, I expect, _noticing_ that anything was going awry. I fear that in my absence my former servants have been quite outmatched in this battle of wits."

Harry was having a bit of trouble taking this in, but decided, after some thought, that now was not the time to try to work it out. Whether Lord Voldemort believed it was not decisive; Harry would have to evaluate this accusation on his own.

Professor Quirrell's mention of his _servants_ had reminded Harry of something else that he was... obligated, Harry supposed, to ask. The bad news was predictable. On any other day it would have been horrible. Today it would just wash out in the flood. "Bellatrix Black," Harry said. "What was the truth about her?"

"She was broken inside before I ever met her," Professor Quirrell said. He picked up what looked like a white-grey rubber band and held it over the cauldron; as the rubber was held within the steam, it turned black. "Using Legilimency on her was a mistake. But that glimpse showed me how easy it would be to make her fall in love with me, so I did. Ever after she was the most faithful of all my servants, the only one I could almost trust. I had no intention of giving her what she wanted from me; so I commended her to the Lestrange brothers for their use, and the three of them were happy in their own special way."

"I doubt it," Harry's mouth said, mostly on autopilot. "If that were true, Bellatrix wouldn't have remembered who the Lestrange brothers were, when we found her in Azkaban."

Professor Quirrell shrugged. "You may be right."

"What the hell were we actually doing there?"

"Finding out where Bellatrix had put my wand. I had told the Death Eaters of my immortality, in the hope - now proven futile - that they would stay together for at least a few _days_ if I appeared to die. Bellatrix's instructions were to recover my wand from wherever my body had been slain; and take that wand to a certain graveyard where my spirit would appear before her."

Harry swallowed. The image came to him of Bellatrix Black waiting, waiting, waiting at the graveyard, in increasing desperation... it was no wonder she hadn't been thinking strategically when she attacked the Longbottom household. "What did you do with Bellatrix once she was out?"

" _Ssent her to a peaceful place to recover sstrength_ ," Professor Quirrell said. A cold smile. "I had a use remaining for her, or rather a certain portion of her, and on my future plans I shall not answer questions."

Harry breathed deeply, trying to maintain control. "Were there any other secret plots in this school year?"

"Oh, a fair number, but not many more that concern you, not that I can think of offhand. The true reason I demanded to try to teach the Patronus Charm to first-years was to bring a Dementor before your own person, and then I arranged for your wand to fall where the Dementor could continue to drain you through it. _Wass no malice in it, only hopess that you would recover ssome of your true memoriess._ That was also why I arranged for certain witches to pull you down from the air during your rooftop episode, so I could appear to save your life; just in case any suspicion fell on me during the Dementor incident I had scheduled for shortly after. _Alsso no malice there._ I arranged some of the attacks on Miss Granger's group, so that the attacks could be defeated; I do rather dislike bullies. _Think that iss all ssecret plotss concerning you from thiss sschool-year, unless I have forgotten ssomething._ "

 _Life lesson learned,_ said his Hufflepart. _Try to resist the temptation to randomly meddle in other people's lives. Like, you know, Padma Patil's life. If you don't want to end up like this, that is._

Harry swallowed, controlling his breathing. Professor Quirrell had just added a tuft of horsehair to the _potion of effulgence,_ and that was very late in the potion, if Harry remembered correctly. There weren't many bellflowers left in the heap to be added, either.

It was probably time to stop worrying so much about risk and play this conversation less conservatively, all things considered.

"I have already pointed out one of your mistakes by accident," Harry said, trying to keep his voice level, "if I point out another, will you punish me for it?"

Professor Quirrell lifted his eyebrows. "Not if the mistake is a real one. I do not suggest that you moralise at me. But I would not curse the bearer of bad news, nor the subordinate who makes an honest attempt to point out a problem. Even as Lord Voldemort I could never bring myself to that stupidity. Of course, there were some fools who mistook my policy for weakness, who tried to thrust themselves forward by pushing me down in their public counsel, thinking me obliged to tolerate it as criticism." Professor Quirrell smiled reminiscently. "The Death Eaters were better off without them, and I do not advise you make the same mistake."

Harry nodded. "When you told me about what happened in Godric's Hollow, on Halloween night... I thought I saw another flaw in your reasoning. A way you could have avoided disaster. I believe you have a blind spot, a class of strategies you don't consider, so you didn't see it even afterward-"

"I hope you are not about to say anything stupid along the lines of 'don't try to kill people'," Professor Quirrell said. "I shall be unhappy if that is the case."

" _Not valuess difference. True misstake, given your goalss. Will you hurt me, if I act the part of the teacher toward you, and teach lessson? Or if misstake is ssimple and obviousss, and makess you feel sstupid?"_

" _No,_ " hissed Professor Quirrell. " _Not if lessson iss true._ "

Harry said, "Why didn't you test the horcrux system before you actually had to use it?"

"Test it?" said Professor Quirrell. He looked up from the brewing potion, and indignation came into his voice. "What do you mean, _test it?_ "

"Why didn't you test if the horcrux system was working correctly, before you needed it on Halloween?"

Professor Quirrell looked disgusted. "You ridiculous - I didn't want to _die,_ Mr. Potter, and that was the only way to test my great creation! What good would it have done to risk my life sooner rather than later? How would I have been better off?"

Harry swallowed a lump in his throat. " _There wass way for you to tesst your horcrux ssysstem without dying._ The general lesson is important. Do you see it now?"

"No," Professor Quirrell said after a while. The Defense Professor gently crumbled one of the last bellflowers together with a strand of long blonde hair and then dropped it into the potion, which was bubbling brighter, now. Only two more bellflowers remained on the Potions table. "And I do hope your lesson is a sensible one, for your sake."

"Suppose, Professor, that I learned how to cast the improved horcrux spell and I was willing to use it. What would I do with it?"

Professor Quirrell answered at once. "You would find some person whom you found morally abhorrent and whose death you could convince yourself would save other lives, and murder them to create a horcrux."

"And then what?"

"Make more horcruxes," said the Defense Professor. He picked up a jar of what looked like dragon scales.

"Before that," Harry said.

After a time the Defense Professor shook his head. "I still do not see it, and you will cease this game and tell me."

"I would make horcruxes for my friends. You have a blind spot around strategies that involve doing nice things for other people, to the point where it stops you from achieving your selfish values. You think... it's not your style, I suppose. That... particular part of your self-image... is what cost you those nine years."

The dropper of mint oil that the Defense Professor was holding added liquid to the cauldron, drip by drip.

"I see..." the Defense Professor said slowly. "I see. I should have taught Rabastan the advanced horcrux ritual, and forced him to test the invention. Yes, that is supremely obvious in retrospect. For that matter, I could have ordered Rabastan to try marking himself onto some disposable infant, to see what happened, before I took myself to Godric's Hollow to create you." Professor Quirrell shook his head bemusedly. "Well. I am glad I am realizing this now and not ten years earlier; I had enough to chide myself for at that time. Indeed, now that you have pointed it out, I have just now thought of some nice things I can do for other people this very day, to further my agenda."

"The error is more general than that, in fact. You have a small, but consistent error in your models of other people. I suspect it is because you imagine what other people would do by imagining them as an inferior version of yourself that is wearing a mask of alternative values. How inferior that version is depends on how competent the person in question is."

"That is a fair observation," said Professor Quirrell. "What is your point?"

"Well,", said Harry, "That is good enough for most purposes, but it is not perfect. You expect other people to effectively have two sets of values - ones fairly close to yours, and ones they pretend to have and thus actively demonstrate. This leads you to predict the other person would drop the mask in response to a certain line of questioning, when, in fact, they have no mask to drop, since most people only have one set of values."

"Mister Potter," snorted Professor Quirrell, "If that were the case, the world would look very different. Students would not procrastinate, husbands wouldn't cheat and priests would never be caught lying. My experience tells me it is clearly not so."

Harry shrugged, "Your experience is not much of an indicator here, given that you clearly aren't very good at modelling people."

"I beg your pardon?"

"Well, let's see what I know of your attempts to use diplomacy and persuasion on people, which would serve as an indicator of your ability to model others. Correct me if I am wrong on any count. You have"- Harry bent one finger - "one, entirely failed to persuade a small and tightly knit country to stand against a group of terrorists of all things, which would be child's play to any Muggle politician. Two, failed to get accepted into a Muggle martial arts school without resorting to mind affecting magic. Three, failed to get accepted into the defence professor post despite your high qualifications for the position. Four, your largest project that involved direct management of a group of people was you controlling a very small band of criminals with torture and intimidation, which even a blind crippled monkey could have managed. I have to say, this doesn't look very good. Oh, and five, that band dissolved just days after your disappearance, despite your hopes, and in a fashion entirely predictable by any Muggle psychologist. Really not impressed at the moment."

Professor Quirrell seemed irritated by this. "Cherry picking my failures, are you, mister Potter? I have plenty of successes to my name in this regard, as the last war could indicate."

Harry shook his head. "Modelling social interactions within groups and modelling what someone would do in stressful conditions of tactical combat given the information known to them are not the same thing. You can be good at one and bad at the other. I know that you aren't good at the former, because I inherited some of those methods of thinking from you. I got into the debt to the Malfoys, and got into the confrontation with Snape at the start of the year, by using those methods. I got out of the debt without them. You think of forcing someone into an action, instead of making it so that they think the action is in their interest, and in fact has been their idea all along, and there is a key difference there."

Professor Quirrell stayed silent for a while. "I suppose there is little harm in humouring you on this. Do explain your theory for how humans think."

"It isn't mine. This is just what I know of Muggle theory of mind. The reason you think people only having one set of values would lead to, say, husbands never cheating, is that you are missing the second element of the picture. This is something Muggles know better than Wizards - humans have, in some sense, two methods of thinking, and only one of those is a conscious one. When they have time and inclination to think and analyse the situation, they can act according to their actual set of values, as best as their abilities allow them. That is rare, however, and most of the time they act according to the second method of thinking. You...could call it habit-based? Things are done often enough until it is so easy to do that people continue to do it even when factors that made the original behaviour worthwhile no longer exist. Some of those behaviours are learned, while others, such as seeking higher status, have been made innate to the human brain by thousands years of history. The discrepancy between these two methods of thinking is what you notice when you say you do not know how normal people think."

Professor Quirrell was frowning at this, "I assume that isn't the entire story either. Even with how blind people tend to be, they would notice engaging in such a behaviour as often as you claim."

Harry nodded. "Yes. But the human mind is not as unified as people think. One part of the brain can be performing an action according to a simple habitual rule, while another rationalises a reason for how that action could be caused by their values. As such, value conflict is only noticed when it is already suspected by the person themselves, you perceive."

Professor Quirrell raised an eyebrow "One _part_ of their mind? I admit I have never been interested in medical techniques, but even I know most people only have one personality."

Harry hissed, " _Iss true._ It was shown to work this way in a series of experiments with patients who had the connection between their hemispheres cut. Throw some selective memorisation and inherent political instinct to never admit being wrong into the mix, and most people would not notice that they are acting against their values even as they are doing so."

Professor Quirrell smiled. "An intriguing theory. Are you going somewhere with this, child?"

Harry's gaze grew hard. "Yes. Most people are simply not good enough liers to consistently lie without being caught. And the best way to lie is to actually believe your own lie. Evolution - I presume you know that much of Muggle studies of biology - thus ensures people actually _think_ they hold only a single set of values, while actually effectively holding two. You, on the other hand, expect them to have two _conscious_ ones. That is why your seduction of Hermione to the dark side failed - you expected her to have a set of values more akin to your own below the one she has shown outwardly, when she had none. This is why our mission to Azkaban almost ended in disaster - you had not expected me to care about the lives of enemy combatants as much as I do. And this is why you failed to expect what I would do during Hermione's trial, and thus failed to prevent those events by, for example, sending me a message regarding you having a plan in progress. _And_ this is why you still can hardly understand the reason why that clerk denied your application for the Asian magic instructor, despite having used legilimency on him, even though the principle behind his actions would be as clear as day to any Muggle researcher."

Professor Quirrell stayed silent again. "I confess I have not extensively studied what Muggles know of the mind. I believed there to be little point in it, with the knowledge of legilimency I possessed. If what you speak is true, it would seem that I was quite wrong in that regard, and this is a valuable point indeed."

The second-to-last bellflower was dropped into the potion, gently.

"Any other valuable lessons you would like to teach to Lord Voldemort, boy?" said Professor Quirrell. He was looking up from the potion, and grinning as though he knew exactly what Harry was thinking.

"Well," Harry sighed. "I presume you know that doing nice things for other people feels better than doing them for yourself?"

"Do you _really_ think I never thought of that, boy?" The smile had vanished. "Do you think I am stupid? After graduating Hogwarts I wandered the world for years, before I returned to Britain as Lord Voldemort. I have put on more faces than I bothered counting. Do you think I never tried to play the hero, just to see how it would feel? Have you come across the name of Alexander Chernyshov? Under that guise, I sought out a forlorn hellhole ruled over by a Dark Wizard, and I freed the wretched inhabitants from their bondage. They wept tears of gratitude for me. It did not feel like anything in particular. I even stayed about and killed the next five Dark Wizards to try taking command of the place. I spent my own Galleons - well, not my own Galleons, but the same principle applies - to prettify their little country and introduce a semblance of order. They groveled all the more, and named one in three of their infants Alexander. I still felt nothing, so I nodded to myself, wrote it off as a fair try, and went upon my way."

"And were you happy as Lord Voldemort, then?" Harry's voice had risen, grown wild.

Professor Quirrell hesitated, then shrugged. "It appears you already know the answer to that."

"Then _why?_ Why be Voldemort if it _doesn't even make you happy?_ " Harry's voice broke. "I'm _you_ , I'm based on you, so _I know_ that Professor Quirrell isn't just a mask! I _know_ he's somebody you really could have been! Why not just stay that way? Take your curse off the Defense Position and just _stay here_ , use the Philosopher's Stone to take David Monroe's shape and let the real Quirinus Quirrell go free, I'll swear not to tell anyone who you really are, just _be Professor Quirrell,_ for always! Your students _would_ appreciate you, my father's students appreciate _him_ -"

Professor Quirrell was chuckling over the cauldron as he stirred it. "There are perhaps fifteen thousand wizards living in magical Britain, child. There used to be more. There's a reason they're afraid to speak my name. You'd forgive me that because you liked my Battle Magic lessons?"

 _Seconded,_ said Harry's inner Hufflepuff. _Seriously, what the hell?_

Harry kept his head raised, though it was trembling. "It's not my place to forgive anything you've done. But it's better than another war."

"Ha," said the Defense Professor. "If you ever find a Time-Turner that goes back forty years and can alter history, be sure to tell Dumbledore that before he rejects Tom Riddle's application for the Defense position. But alas, I fear that Professor Riddle would not have found lasting happiness in Hogwarts."

" _Why not?_ "

"Because I still would've been surrounded by idiots, and I wouldn't have been able to kill them," Professor Quirrell said mildly. "Killing idiots is my great joy in life, and I'll thank you not to speak ill of it until you've tried it for yourself."

Harry opened his mouth to search for a response, but found none.

"And _you_ ," said Professor Quirrell, "have no right to speak of happiness either. Happiness is not what you hold precious above all. You decided that in the beginning, all the way back in the beginning of this year, when the Sorting Hat offered you Hufflepuff. Which I know about, because I received a similar offer and warning all those years ago, and I refused it just as you did. Beyond this there is little more to say, between Tom Riddles." The Defense Professor turned back to the cauldron.

Before Harry could think of any way to reply, Professor Quirrell dropped in the last bellflower, and a burst of glowing bubbles boiled up from the cauldron.

"I believe we are done here," Professor Quirrell said. "If you have further questions, they must wait."

 _There is little more to say, between Tom Riddles,_ said Professor Quirrell. This line clicked something in Harry's head, and he realised what bothered him in Professor Quirrell's story about that night of October 1981.

 _There is little more, between Tom Riddles._

There was one thing between Tom Riddles. Two phrases, said so long ago it was almost as if it was in another life entirely.

 _And either must destroy all but a remnant of the other, for those two different spirits cannot exist in the same world._

 _No, Potter. The prophecy is not yet fulfilled. I would know if it were._

Professor Quirrell seemed to think the prophecy was fulfilled by him overwriting Harry's spirit with his own, and Harry destroying Voldemort's body. But that...did not seem to fit. The prophecy seemed to imply active action on the part of both of those mentioned. _Harry_ did not destroy Voldemort's body - it was the resonance between their magics. More than that, Professor Quirrell seemed to care little for his body, and his memories and personality survived intact.

He was not a remnant of his former self, but pretty much the whole thing.

In other words, the prophecy was only fulfilled _halfway_. And the part that was not yet fulfilled...my, it was just the thing Harry desperately needed. _Leverage._

Harry couldn't help but smile as he shakily rose to his feet. Fortunately, Professor Quirrell's back was turned, as he took up the cauldron and poured out a ridiculously huge volume of effulgent liquid, more than seemed like it could fit in a dozen cauldrons, onto the purple fire that guarded the doorway.

Harry quickly schooled his features into the mask of someone who had absolutely no idea how to strongarm Voldemort himself. This could wait. They had a stone to steal.

The purple fire winked out.

"Now for the Mirror," said Professor Quirrell, and he drew forth the Cloak of Invisibility from his robes, and floated it to drop before Harry's shoes.


	5. Chapter 5

**Author notes:**

* * *

 **A bit of this chapter is copied from Minds, Names and Faces - another HPMOR recursive fanfic, that I fully recommend you to read.**

* * *

 _Even the greatest artifact can be defeated by a counter-artifact that is lesser, but specialized._

That was what the Defense Professor had told Harry, after dropping the True Cloak of Invisibility to pool in fuliginous folds near Harry's shoes.

 _The Mirror of Perfect Reflection has power over what is reflected within it, and that power is said to be unchallengeable. But since the True Cloak of Invisibility produces a perfect absence of image, it should evade this principle rather than challenging it._

There had followed a series of questions in Parseltongue establishing that Harry currently did not intend to do anything stupid or try to run away, and further reminders that Professor Quirrell could sense him and had spells to detect the Cloak and that Hermione would not be resurrected without the stone.

Then Harry was told to don the Cloak, open the door that lay beyond the quenched fires, and advance through the door into the final chamber; as Professor Quirrell stood well back, outside of that door's sight.

The last chamber was illuminated in lights of soft gold, and the stone walls were of gentle white and faced with marble.

In the center of the room stood a simple and unornamented golden frame, and within the frame was a portal to another gold-illuminated room, beyond whose door which lay another Potions chamber; that was what Harry's brain told him. The Mirror's transformation of light was so perfect that conscious thought was required to deduce that the room inside the frame was only a reflection, rather than a portal. (Though it might have been easier to intuit if Harry hadn't been invisible, just then.)

The Mirror did not touch the ground; the golden frame had no feet. It didn't look like it was hovering; it looked like it was fixed in place, more solid and more motionless than the walls themselves, like it was nailed to the reference frame of the Earth's motion.

"Is the Mirror there? Is it moving?" came Professor Quirrell's commanding voice from the Potions Chamber.

" _Iss there,_ " Harry hissed back. " _Not moving._ _Doesn't look like it can move._ "

Again tones of command rang forth. "Walk around to the back of the Mirror."

From behind, the golden frame appeared solid, showing no reflections, and Harry said so in Parseltongue.

"Now take off your Cloak," commanded Professor Quirrell's voice still from within the Potions room. "Report to me at once if the Mirror moves to face you."

Harry slowly took off his Cloak, ready to put it back on if the Mirror was going to start rotating.

The Mirror remained nailed to the reference frame of Earth's motion; and Harry reported this.

Shortly after there came a hissing and seething, and a balefire phoenix melted through the marble wall behind Harry, the ambient light in the room taking on a red tinge as it entered.

Professor Quirrell ordered Harry to walk along that corridor out of the room, and then back in, to see if the Mirror would react in any way to someone entering the room from a new direction.

Finally, Professor Quirrell followed behind him, walking out of the new-made corridor that had been carved. "Well," Professor Quirrell said, "that is one possible trap averted. And now..." Professor Quirrell exhaled. "Now we will think of possible strategies for retrieving the Stone from the Mirror, and you will try them; for I prefer not to let my own image be reflected. I give you fair warning, this is the part that may prove tedious."

"I take it this isn't a problem you can solve with Fiendfyre?"

"Ha," said Professor Quirrell, and gestured.

The balefire phoenix moved forward in a rush of crimson terror, the red light casting writhing shadows on the remaining marble walls. Harry jumped back before he could think.

The dreadful dark-red blaze rushed past Professor Quirrell, surged into the golden back of the Mirror, and disappeared as fast as it touched the gold.

Then the fire was gone, and the room was tinged scarlet no more.

There was no scratch upon the golden surface, no glow to mark the absorption of heat. The Mirror had simply remained in place, untouched.

Chills went down Harry's spine. If he'd been playing Dungeons and Dragons and the dungeon master had reported that result, Harry would have suspected a mental illusion, and rolled to disbelieve.

Upon the center of the golden back had appeared a sequence of runes in no known alphabet, black absences of light in small lines and curves, arranged in a level horizontal row. The thought occurred to Harry that some minor concealing illusion had been consumed in the Fiendfyre, a far lesser enchantment that had been added to prevent children from seeing those letters…

"How old is this Mirror?" Harry said in almost a whisper.

"Nobody knows, Mr. Potter." The Defense Professor reached out his fingers toward the runes, a look of something like reverence on his face; but his fingers did not touch the gold. "But my guess is the same as yours, I think. It is said, in certain legends that may or may not be fabrications, that this Mirror reflects _itself_ perfectly and therefore its existence is absolutely stable. So stable that the Mirror was able to survive when every other effect of Atlantis was undone, all its consequences severed from Time. You can see why I was amused when you suggested Fiendfyre." The Defense Professor let his hand fall.

Even in the middle of everything else, Harry felt the awe, if that was true. The golden frame gleamed no brighter than before, for all the revelation; but you could imagine it going back, and back, into a civilization that had been made to never be... "What - does the Mirror _do,_ exactly?"

"An excellent question," said Professor Quirrell. "The answer is in the runes that are written upon the Mirror's golden frame. Read them to me."

"They're not in any alphabet I recognize. They look like randomly oriented chicken-scratches drawn by Tolkien elves."

"Read them anyway. _Iss not dangerouss._ "

"The runes say, _noitilov detalo partxe tnere hoc ruoy tu becafruoy ton wo hsi -_ " Harry stopped, feeling more prickles at his spine.

Harry knew what the rune for noitilov _meant_. It meant noitilov. And the next runes said to detalo the noitilov until it reached partxe, then keep the part that was both tnere and hoc. That belief felt like knowledge, like he could have answered 'Yes' with confident authority if somebody asked him whether the ton wo was ruoy or becafruoy. It was just that when Harry tried to relate those concepts to any other concepts, he drew a blank.

 _"Do you undersstand what wordss mean, boy?"_

 _"Don't think sso."_

Professor Quirrell gave a soft exhalation, his eyes not leaving the golden frame. "I had wondered if perhaps the Words of False Comprehension might be understandable to a student of Muggle science. Apparently not."

"Maybe -" Harry began.

 _Really, Ravenclaw?_ said Slytherin. _You're pulling this_ _NOW?_

"Maybe I could try again to understand the words if I knew more about the Mirror?" said Harry's Ravenclaw part, which had assumed direct control.

Professor Quirrell's lips quirked up. "As with most ancient things, scholars have written down enough lies that it is hard to be sure of anything by now. It is definite that the Mirror is at least as old as Merlin, for it is known that Merlin used it as a tool. It is also known that after his death, Merlin left written instructions that the Mirror did not need to be sealed away, despite it having certain powers that might normally cause one to worry. He wrote that, given how painstakingly the Mirror had been crafted to not destroy the world, it would be easier to destroy the world using a lump of cheese."

This statement struck Harry as not entirely reassuring.

"Certain other facts about the Mirror are attested by famous wizards who were reasonably skeptical, and whose word has otherwise proven reliable. The Mirror's most characteristic power is to create alternate realms of existence, though these realms are only as large in size as what can be seen within the Mirror; it is known that people and other objects can be stored therein. It is claimed by several authorities that the Mirror alone of all magics possesses a true moral orientation, though I am not sure what that could mean in practical terms. I would expect moralists to call the Cruciatus Curse by their name of 'evil' and the Patronus Charm by their name of 'good'; I cannot guess what a moralist would think was any _more_ moral than that. But it is claimed, for example, that phoenixes came into our world from a realm that was evoked inside this Mirror."

Words like _Jeepers_ and what his parents would have termed inappropriate language were all running through Harry's head, none very coherently, as he stared at the golden back of the Mirror.

"I have wandered the world and encountered many stories that are not often heard," said Professor Quirrell. "Most of them seemed to me to be lies, but a few had the ring of history rather than storytelling. Upon a wall of metal in a place where no one had come for centuries, I found written the claim that some Atlanteans foresaw their world's end, and sought to forge a device of great power to avert the inevitable catastrophe. If that device had been completed, the story claimed, it would have become an absolutely stable existence that could withstand the channeling of unlimited magic in order to grant wishes. And also - this was said to be the vastly harder task - the device would somehow avert the inevitable catastrophes any sane person would expect to follow from that premise. The aspect I found interesting was that, according to the tale writ upon those metal plates, the rest of Atlantis ignored this project and went upon their ways. It was sometimes praised as a noble public endeavor, but nearly all other Atlanteans found more important things to do on any given day than help. Even the Atlantean nobles ignored the prospect of somebody other than themselves obtaining unchallengeable power, which a less experienced cynic might expect to catch their attention. With relatively little support, the tiny handful of would-be makers of this device labored under working conditions that were not so much dramatically arduous, as pointlessly annoying. Eventually time ran out and Atlantis was destroyed with the device still far from complete. I recognise certain echoes of my own experience that one does not usually see invented in mere tales." A twist in the dry smile. "But perhaps that is merely my own preference for one tale among a hundred other legends. You perceive, however, the echo of Merlin's statement about the Mirror's creators shaping it to not destroy the world. Most importantly for our purposes, it may explain why the Mirror would have the previously unknown capability that Dumbledore or Perenelle seems to have evoked, of showing any person who steps before it an illusion of a world in which one of their desires has been fulfilled. It is the sort of sensible precaution you can imagine someone building into a wish-granting creation meant to not go horribly wrong."

"Wow," Harry whispered, and meant it. This was Magic with a capital M, the sort of Magic that appeared in _So You Want To Be A Wizard,_ not just a collection of random physics-violating things you could do with a wand.

Professor Quirrell gestured at the golden back. "The final property upon which most tales agree, is that whatever the unknown means of commanding the Mirror - of that Key there are no plausible accounts - the Mirror's instructions cannot be shaped to react to individual people. So it is not possible for Perenelle to command this Mirror, 'only give the Stone to Perenelle'. Dumbledore cannot state, 'Only give the Stone to one who wishes to give it to Nicholas Flamel'. There is in the Mirror a blindness such as philosophers have attributed to ideal justice; it must treat all who come before it by the same rule, whatever rule may be in force. Thus, there must be some rule for reaching the Stone's hiding-place which anyone can invoke. And now you see why _you_ , called the Boy-Who-Lived, shall implement whatever strategies the two of us devise. For it was said that this thing possesses a moral orientation, and it may have been given commands reflecting the same. I am well aware that on conventional terms you are said to be Good, just as I am said to be Evil." Professor Quirrell smiled, rather darkly.

Harry had a thought. It was a crazy thought, but he had crazier ones that still worked. He reached for his pouch, then with annoyance found it wasn't at his belt.

"Professor Quirrell?" said Harry. "I am going to need a quotes quill from my pouch and a piece of paper."

Professor Quirrell raised an eyebrow. "Did you think of something, boy? Speak."

"A way to maybe parse the runes, but it's unlikely to work. _No way thiss can harm or endanger you, I think. No trickss._ "

Professor Quirrell smirked. "This, I'd like to see."

Harry took the offered Quill, put the paper down on the ground and set the Quill on it.

"Transcribe everything I say in the english alphabet. If that can't be done, use the International Phonetic Alphabet instead."

He read the runes aloud once more. The Quill scratched mechanically over a scrap of parchment.

 _Noitilov detalo partxe tnere hoc ruoy tu becafruoy ton wohsi._

Harry read it backwards. "Um... 'I show not your face, but your coherent extrapolated volition. Wow, I can't believe this actually worked.'"

Professor Quirrell was staring at him.

And then he began to laugh.

Harry had seen Professor Quirrell smile before, and give short, sardonic chuckles, but this was wild, genuine laughter, almost like Dumbledore had done when Harry had blackmailed him. Harry had never once expected to see the dignified Defence Professor double over, clutching at his sides, but there he was.

Professor Quirrell collected himself with visible effort. "Ah, Mr. Potter," another chuckle, "It is known that even the greatest artifact can be defeated by a lesser, yet specialised counter-artifact," another burst of laughter, "and yet I never expected the last legacy of Atlantis to be brought low by a one galleon curiosity."

Despite how tense the overall situation was getting, Harry couldn't help but laugh as well.

Finally, Professor Quirrell said, "Well. This confirms and clarifies the theories for how the mirror can be blind to a specific person. It presumably only reacts to your volition, and so as our first attempt - though not our last, rest assured-let us see what this Mirror makes of your attempt to retrieve the Stone in order to save the life of Hermione Granger and hundreds of your fellow students."

"Ah. So that is why you counter-productively threatened me from the start."

"Yes."

"And the _first_ version of that plan," said Harry, who was beginning to finally understand, "the one you invented on Friday in my first week of Hogwarts, called for the Stone to be retrieved by Dumbledore's golden child, the Boy-Who-Lived, making a selfless and noble attempt to save the life of his dying Defense teacher, Professor Quirrell."

"Of course," said Professor Quirrell.

It was a poetical sort of plot, Harry supposed, but his appreciation of that elegance was being hampered by the surrounding circumstances.

Then another thought occurred to Harry.

"Um," Harry said. "You think that this Mirror is a trap for you -"

"There is no way beneath the heavens that it is not meant as a trap."

"That is to say, it's a trap for Lord Voldemort. Only it can't be a trap for him personally. There has to be a general rule that underlies it, some generalizable quality of Lord Voldemort that triggers it." Without conscious awareness, Harry was frowning hard at the Mirror's golden back.

"As you say," said Professor Quirrell, who was beginning to frown at Harry's frowning.

"Well, on the first Thursday of this year, the mad Headmaster Dumbledore, who I'd just seen incinerate a chicken, told me that I had no chance whatsoever of getting into his forbidden corridor, since I didn't know the spell _Alohomora._ "

"I _see,_ " said Professor Quirrell. "Oh, dear. I wish you had thought to mention this to me a good deal earlier."

Neither of them needed to state aloud the obvious, that this bit of reverse reverse psychology had successfully ensured that Harry would stay the heck away from Dumbledore's forbidden corridor.

Harry was still concentrating. "Do you think Dumbledore suspects that I am, in his terms, a horcrux of Lord Voldemort, or more generally, that some aspects of my personality were copied off Lord Voldemort?" Even as Harry asked this aloud, he realized what a dumb question it was, and how much completely blatant evidence he'd already seen that -

"Dumbledore cannot _possibly_ have missed it," said Professor Quirrell. "It is not exactly subtle. What else is Dumbledore to think, that you are an actor in a play whose stupid author has never met a real eleven-year-old? Only a gibbering dullard would believe that - ah, never mind."

The two of them stared at the Mirror in silence.

Finally Professor Quirrell sighed. "I have outwitted myself, I fear. Neither you nor I dare be reflected in this Mirror. I suppose I must command Professor Sprout to undo my Obliviations of Mr. Nott and Miss Greengrass... You see, the other great difficulty of the Mirror is that the rule by which it treats those reflected will disregard external forces, such as False Memories or a Confundus Charm. The Mirror reflects only those forces arising from within the person themselves, the states of mind they arrive at through their own choices; so it is said in several places. That is why I had Mr. Nott and Miss Greengrass, believing different stories about why the Stone's extraction was necessary, ready to appear before this Mirror." Professor Quirrell rubbed at the bridge of his nose. "I constructed other stories for other students, ready for me to set into motion with the chosen trigger... but as this day approached, I began to feel pessimistic about the project. Such as Nott and Greengrass still seem worth trying, if we cannot think of something better. But I wonder if Dumbledore has tried to construct this puzzle to specifically resist Voldemort's cunning. I wonder if he might have succeeded."

Again they stared at the mirror in silence, the elder Tom Riddle and the younger.

"I suspect, Professor," Harry said after a time, "that your entire class of hypotheses about somebody needing to want the Stone for good or honest purposes is mistaken. The Headmaster wouldn't set a retrieval rule like that."

"Why?"

"Because Dumbledore knows how easy it is to end up believing that you're doing the right thing when you're actually not. It'd be the first possibility he imagined."

Professor Quirrell nodded. "Your point is well taken."

"I'm not sure why you think this puzzle is solvable," Harry said. "Just set a rule like, your left hand must hold a small blue pyramid and two large red pyramids, and your right hand must be squeezing mayonnaise onto a hamster - no, nevermind, the rule must be about deep desires of the person, so unless they deeply _want_ that to happen it can't apply..."

"Indeed," Professor Quirrell said. "The legends are unclear on what rules can be given, but I think it must have something to do with the Mirror's original intended use - it must have something to do with, as the runes say, volition. Squeezing mayonnaise onto a hamster will not qualify as that, for most people."

"Huh," Harry said. "Maybe the rule is that the person has to not want to use the Stone at all - no, that's too easy, the story you gave Mr. Nott solves it."

"In some ways you may understand Dumbledore better than I," said Professor Quirrell. "So now I ask you this: how would Dumbledore use his notion of the acceptance of death to guard this Stone? For that above all he thinks I cannot comprehend, and he is not far wrong."

Harry thought about this for a while, considering several ideas and discarding them, until he found one that he couldn't dismiss so easily.

Reluctantly, Harry spoke. "Would Dumbledore think that this Mirror could reach the afterlife? Could he put the Stone into something that he _thinks_ is an afterlife, so that only people who believe in an afterlife can see it?"

"Hm..." Professor Quirrell said. "Possibly... yes, there is a certain plausibility to it. Using this setting of the Mirror to show people their heart's desires... Albus Dumbledore would see himself reunited with his family. He would see himself united with them _in death,_ wanting to die himself rather than wishing for them to be returned to life. His brother Aberforth, his sister Ariana, his parents Kendra and Percival... it would be Aberforth to whom Dumbledore gave the Stone, I think. Would the Mirror recognize that Aberforth particularly had been given the Stone? Or will any person's dead relative do, if that person believes their relative's spirit would give them back the Stone?" Professor Quirrell was pacing in a short circle, keeping well away from Harry and the Mirror as he moved. "But all this is only one idea. Let us devise another."

Harry began to tap his cheek, then stopped abruptly as he realized where he'd picked up that gesture. "What if Perenelle is the one who put the Stone in here? Maybe she keyed the Mirror to give the Stone only to the person who put it in originally."

"Perenelle has lived this long by knowing her limitations," said Professor Quirrell. "She does not overestimate her own intellect, she is not prideful, if that were so she would have lost the Stone long ago. Perenelle will not try to think of a good Mirror-rule herself, not when Master Flamel can leave the matter in Dumbledore's wiser hands... but the rule of only returning the Stone to the one who remembers placing it, also works if Dumbledore himself has placed the Stone. It would be a hard rule to bypass, since I cannot simply Confund someone into believing that they put in the Stone... I would have to create a false Stone, and a false Mirror, and arrange the drama..." Professor Quirrell was frowning, now. "But it is still something that Dumbledore would imagine Voldemort being able to arrange, given time. If at all possible, Dumbledore will want to make the key to the Mirror a state of mind he thinks I _cannot_ arrange in a pawn - or a rule that Dumbledore thinks Voldemort can never comprehend, such as a rule involving the acceptance of one's own death. That is why I considered your previous idea plausible."

Then Harry had an idea.

He was not sure if it was a good idea.

...it wasn't like they had any better ones.

"Arguendo," Harry said. "We're not sure what's necessary to retrieve the Stone. But a _sufficient_ condition should involve Albus Dumbledore, or maybe someone else, in a state of mind where they believe that the Dark Lord has been defeated, that the threat is over, and that it is time to take out the Stone and give it back to Nicholas Flamel. We aren't sure which part of that person's state of mind, let's say Dumbledore's, will be the necessary part that he thinks Lord Voldemort can't understand or duplicate; but under those conditions Dumbledore's entire state of mind will be _sufficient._ "

"Reasonable," said Professor Quirrell. "So?"

"The corresponding strategy," Harry said carefully, "is to mimic Dumbledore's state of mind under those conditions, in as much detail as possible, while standing in front of the mirror. And this state of mind must have been produced by internal forces, not external ones."

"But how are we to get that without Legilimency or the Confundus Charm, both of which would certainly be external - ha. I _see._ " Professor Quirrell's ice-pale eyes were suddenly piercing. "You suggest that I Confund _myself,_ as you cast that hex upon yourself during your first day in Battle Magic. So that it is an internal force and not an external one, a state of mind that comes about through only my own choices. Say to me whether you have made this suggestion with the intention of trapping me after I retrieve the stone, boy. Say it to me in Parseltongue."

" _My mind that you assked to devisse sstrategy may perhapss have been influenced by ssuch an intent - who knowss? Knew you would be ssusspiciouss, assk thiss very question. Decission is up to you, teacher. I know nothing you do not know, about whether thiss iss likely to trap you. Do not call it betrayal by me if you choosse thiss for yoursself, and it failss. You know I want the sstone ass much ass you._ " Harry felt a strong impulse to smile, and suppressed it.

"Lovely," said Professor Quirrell, who _was_ smiling. "I suppose there are some threats from an inventive mind that even questioning in Parseltongue cannot neutralize."

* * *

Harry put on the Cloak of Invisibility, at Professor Quirrell's orders, to _sstop the man who sshall believe himsself to be sschoolmasster from sseeing you,_ as Professor Quirrell said in Parseltongue.

"Wearing the Cloak or no, you will stand in range of the Mirror yourself," Professor Quirrell said. "If a gush of lava comes forth, you will also burn. I feel that much symmetry should apply."

Professor Quirrell pointed to a spot near the right of the door through which they'd entered the room, before the Mirror and well back of it. Harry, wearing the Cloak, went to where Professor Quirrell had pointed him, and did not argue. It was better to let a more competent adventurer work uninterrupted.

(Though either way, Harry couldn't see Dumbledore doing the lava thing. Dumbledore was probably sufficiently angry at Voldemort to discard his usual restraint, but lava wouldn't permanently stop an entity that Dumbledore believed to be a discorporate soul.)

Then Professor Quirrell pointed with his wand, and a shimmering circle appeared around where Harry was standing on the floor. This, Professor Quirrell said, would soon become a Greater Circle of Concealment, by which nothing within that circle could be heard or seen from the outside. Harry would not be able to make himself apparent to the false Dumbledore by taking off the Cloak, nor by shouting.

"You _will not_ cross this circle once it is active," Professor Quirrell said. "That would cause you to touch my magic, and while Confunded I might not remember how to halt the resonance that would destroy us both. And further, since I do not want you throwing shoes -"

" _I would not interfere with the extraction of the sstone,"_ , hissed Harry, " _unlesss I expect my interference to improve our chancess of extracting it. I ssaid sso already."_

Professor Quirrell blinked, and stopped mid wand gesture. "It is rather unusual to be dealing with a Harry Potter who shows some sense. Well, regardless."

Professor Quirrell made another gesture, and just within the Greater Circle of Concealment, a slight shimmer appeared in the air, a globe-shaped distortion. " _Thiss barrier will explode if touched, by you or other material thing."_ The resonance might lash at me afterward, but you would also be dead. Now tell me in Parseltongue that you do not intend to cross this circle or take off your Cloak or do _anything_ at all impulsive or stupid. Tell you me you will wait quietly here, under the Cloak, until this is over."

This Harry repeated back.

Professor Quirrell nodded, and said "Since you have been surprisingly sensible during this expedition, I shall ask you this as well. It is likely that the Headmaster would appear before us, and I would have to neutralise him. The barrier around you should serve that purpose as well, forcing him to waste time dispelling it if he wanted to move you off the battlefield. Would you interfere with that? Answer in Parseltongue."

Harry thought about it. He was fairly confident in his new plan. If it worked...well, he would win. Even if it didn't work as Harry intended, Voldemort would probably die anyways, so the world would at least be in the safe status quo again. It would be certainly sad to sacrifice Dumbledore as well...but overall, one life was nothing before all the lives in the world.

" _I will not interfere,"_ hissed Harry. " _Sschoolmasster would be againsst my projectss regardlesss, and would definitely opposse any rational usse of the sstone."_

Professor Quirrell hummed. "If necessary, pretend to be a naive schoolboy again. I intend to use you as a hostage if necessary. _You sshould not be in danger from it. Have planss to ssave both of uss from trapss that I know can come from the mirror._ Though the unexpected can always happen, of course."

Then Professor Quirrell's robes became black tinged with gold, such robes as Dumbledore might wear upon a formal occasion; and Professor Quirrell pointed his own wand at his head.

Professor Quirrell stayed motionless for a long time, still holding his wand to his head. His eyes were closed in concentration.

And then Professor Quirrell said, " _Confundus._ "

At once the expression of the man standing there changed; he blinked a few times as though confused, lowering his wand.

A deep weariness spread over the face Professor Quirrell had worn; without any visible change his eyes seemed older, the few lines in his face calling attention to themselves.

His lips were set in a sad smile.

Without any hurry, the man quietly walked over to the Mirror, as though he had all the time in the world.

He crossed into the Mirror's range of reflection without anything happening, and stared into the surface.

What the man might be seeing there, Harry could not tell; to Harry it seemed that the flat, perfect surface still reflected the room behind it, like a portal to another place.

"Ariana," breathed the man. "Mother, father. And you, my brother, it is done."

The man stood still, as if listening.

"Yes, done," the man said. "Voldemort came before this mirror, and was trapped by Merlin's method. He is only one more sealed horror now."

Again the listening stillness.

"I would that I could obey you, my brother, but it is better this way." The man bowed his head. "He is denied his death, forever; that vengeance is terrible enough."

Harry felt a twinge, watching this, a sense that this was _not_ what Dumbledore would have said, it seemed more like a strawman, a shallow stereotype... but then this wasn't the real Aberforth's spirit either, this was who Professor Quirrell imagined Dumbledore imagined Aberforth was, and that doubly-reflected image of Aberforth wouldn't notice anything amiss…

"It is time to give back the Philosopher's Stone," said the man who thought he was Dumbledore. "It must go back into Master Flamel's keeping, now."

Listening stillness.

"No," said the man, "Master Flamel has kept it safe these many years from all who would seek immortality, and I think it will be safest in his hands... no, Aberforth, I do think his intentions are good."

Harry couldn't control the tension that was running through him like a live wire; he was having trouble breathing. Imperfect, Professor Quirrell's Confundus Charm had been imperfect. The underlying personality of Professor Quirrell was leaking through and seeing the obvious question, why it was okay for Nicholas Flamel himself to have the Stone if immortality was so awful. Even if Professor Quirrell conceptualized Dumbledore as being blind to the question, Professor Quirrell hadn't included a clause in the Confundus saying that _Dumbledore's image of Aberforth_ wouldn't think of it; and all of this was ultimately a reflection of Professor Quirrell's own mind, an image from within the intelligence of Tom Riddle…

"Destroy it?" said the man. "Maybe. I am not sure it _can_ be destroyed, or Master Flamel would have done it long since. I think, many times, that he has regretted making it... Aberforth, I promised him, and we are not so ancient or so wise ourselves. The Philosopher's Stone must go back into the keeping of the one who made it."

And Harry's breath stopped.

The man was holding an irregular chunk of scarlet glass in his left hand, the size perhaps of Harry's thumb from fingernail to the first joint. The sheened surface of the scarlet glass made it seem wet; the appearance was of blood, suspended in time and made into a jagged surface.

"Thank you, my brother," the man said quietly.

 _Is that what the Stone should look like? Does Professor Quirrell know what the true Stone should look like? Will the Mirror give back the real Stone under these conditions, or make an imitation and return that?_

And then -

"No, Ariana," the man said, smiling gently, "I fear I must go now. Be patient, my dearest, it will be soon enough that I join you in truth... why? Why, I am not sure why I must go... when I hold the Stone I am to step aside from the Mirror and wait for Master Flamel to contact me, but I am not sure why I need to step aside from the Mirror to do that..." The man sighed. "Ah, I am getting old. It is well this dreadful war ended when it did. I suppose there is no harm if I speak to you for a time, my dearest, if you wish it so."

A headache was starting behind Harry's eyes; some part of Harry was trying to send a message about not having breathed in a while, but no one was listening. _Imperfect_ , Professor Quirrell's Confundus Charm had been imperfect, Professor Quirrell's image of Dumbledore's image of Ariana wanted to talk to Dumbledore, and maybe didn't want to wait because Professor Quirrell knew on some level that there wasn't really an afterlife, and the previously implanted impulse to leave after getting the Stone _wasn't standing up to Riddle-Ariana's arguments…_

And then Harry felt himself become very calm. He started breathing again.

Either way, there wasn't much Harry could do about it. Professor Quirrell had stopped Harry from intervening; well, hopefully Professor Quirrell had a plan to dodge the consequences of that decision.

The man who thought he was Dumbledore was mostly nodding patiently, sometimes replying to his dearest sister. Sometimes the man cast an uneasy look to one side; as if feeling a strong impulse to go, but suppressing that impulse with the great patience and politeness and concern for his sister that Professor Quirrell imagined Albus Dumbledore having.

Harry saw it the instant the Confundus wore off, and the man's expression changed, becoming again the face of Professor Quirrell.

And in the same instant the Mirror changed, no longer showing Harry the reflection of the room, showing instead the form of the real Albus Dumbledore, as though he were standing just behind the Mirror and visible through it.

The real Dumbledore's face was set, and grim.

"Hello, Tom," said Albus Dumbledore.


	6. Chapter 6

The grimness on Albus Dumbledore's face lasted only an instant before giving way to bewilderment. "Quirinus? What -"

And then there was a pause.

"Well," said Albus Dumbledore. "I do feel stupid."

"I should hope so," Professor Quirrell said easily; if he had been at all shocked himself at being caught, it did not show. A casual wave of his hand changed his robes back to a Professor's clothing.

Dumbledore's grimness had returned and redoubled. "There I am, searching so hard for Voldemort's shade, never noticing that the Defense Professor of Hogwarts is a sickly, half-dead victim possessed by a spirit far more powerful than himself. I would call it senility, if so many others had not missed it as well."

"Quite," said Professor Quirrell. He lifted his eyebrows. "Really, am I that hard to recognise without the glowing red eyes?"

"Oh, yes indeed," Albus Dumbledore said in level tones. "Your acting was perfect; I confess myself utterly deceived. Quirinus Quirrell seemed - what is the term I am looking for? Ah yes, that is the word. He seemed sane."

Professor Quirrell chuckled; he looked for all the world as though the two of them were just having a casual conversation. "I never was insane, you know. Lord Voldemort was just another game for me, the same as Professor Quirrell."

Albus Dumbledore did not look like he was enjoying a casual chat. "I thought you might say that. I regret to inform you, Tom, that anyone who can bring himself to act the part of Voldemort _is_ Voldemort."

"Ah," said Professor Quirrell, raising an admonishing finger. "There is a loophole in that reasoning, old man. Anyone who acts the part of Voldemort must be what moralists call 'evil', on this we agree. But perhaps the real me is completely, utterly, irredeemably evil in an interestingly different fashion from what I was pretending with Voldemort -"

"I find," Albus Dumbledore ground out, "that I do not care."

"Then you must think yourself to be rid of me very soon," said Professor Quirrell. "How interesting. My immortal existence must depend on discovering what trap you have set, and finding a way to escape from it, as soon as possible." Professor Quirrell paused. "But let us pointlessly delay to talk of other matters first. How did you come to be waiting inside the Mirror? I thought you would be elsewhere."

"I am there," Albus Dumbledore said, "and _also_ inside the Mirror, unfortunately for you. I have always been here, all along."

"Ah," said Professor Quirrell, and sighed. "I suppose my little distraction was for naught, then."

And the rage of Albus Dumbledore was no longer leashed. " _Distraction?_ " roared Dumbledore, his sapphire eyes tight with fury. " _You killed Master Flamel for a distraction?_ "

 _Ah_ , thought Harry, _so that's why he said my suggestion for stealing the lore didn't matter anymore._

Professor Quirrell looked dismayed. "I am wounded by the injustice of your accusation. I did not kill the one you know as Flamel. I simply commanded another to do so."

" _How could you? Even you, how could you? He was the library of all our lore! Secrets you have forever lost to wizardry!_ "

There was an edge to Professor Quirrell's smile, now. "You know, I still do not comprehend how your twisted mind can consider it acceptable for Flamel to be immortal, but when I try for the same it makes me a monster."

"Master Flamel never descended into _immortality!_ He -" Dumbledore choked. "He only stayed awake past his evening, for our sakes, through his long, long day -"

"I don't know if you recall this," Professor Quirrell said, his voice airy, "but do you recall that day in your office with Tom Riddle? The one where I begged you, where I went down on my knees and begged you, to introduce me to Nicholas Flamel so that I could ask to become his apprentice, to someday make for myself the Philosopher's Stone? That was my last attempt to be a good person, if you are curious. You told me no, and gave me a lecture on how unvirtuous it was to be afraid of death. I went from your office in bitterness and in fury. I reasoned that if I was to be called evil in any case, just for not wanting to die, then I might as well be evil; and one month later I killed Abigail Myrtle to pursue immortality by other means. Even when I knew more of Flamel, I remained quite put out with your hypocrisy; and for that reason I tormented you and yours more than I otherwise would have done. I have often felt that you ought to know this, but we never had a chance to talk frankly."

"I decline," said Albus Dumbledore, whose gaze did not waver. "I do not accept the tiniest shred of responsibility for what you have become. That was all, entirely, you and your own decisions."

"I am not surprised to hear you say that," said Professor Quirrell. "Well, now I am curious as to what responsibilities you do accept. You have access to some unusual power of Divination; that much I deduced long ago. You made too many nonsensical moves, and the paths by which they worked out in your favor were too ridiculous. So tell me. Were you forewarned of the result, that night of All Hallow's Eve when I was vanquished for a time?"

"I knew," said Albus Dumbledore, his voice low and cold. "For that, I accept responsibility, which is something you will never understand."

"You arranged for Severus Snape to hear the Prophecy that he brought to me."

"I allowed it to happen," said Albus Dumbledore.

"And there I was, all excited at having finally gained my own foreknowledge." Professor Quirrell shook his head as though in sadness. "So the great hero Dumbledore sacrificed his unwitting pawns, Lily and James Potter, merely to banish me for a few years."

Albus Dumbledore's eyes were like stones. "James and Lily would have gone willingly to the death, if they had known."

"And the little baby?" Professor Quirrell said. "Somehow I doubt the Potters would have been so eager to leave him in the path of You-Know-Who."

You could scarcely see the flinch. "The Boy-Who-Lived came out of it well enough. Tried to turn him into _you_ , did you? Instead you turned yourself into a corpse, and Harry Potter became the wizard you should have been." Now there was something like the usual Dumbledore behind the half-moon glasses, a tiny twinkle in those eyes. "All of Tom Riddle's icy brilliance, tamed to the service of James and Lily's warmth and love. I wonder how you felt when you saw what Tom Riddle could have become, if he had grown up in a loving family?"

Professor Quirrell's lips quirked. "I was surprised, even shocked, by the abyssal depths of Mr. Potter's naivete."

"I suppose the humor of the situation would be lost on you." It was then, finally, that Albus Dumbledore smiled. "How I laughed when I realised it! When I saw you had made a Good Voldemort to oppose the evil one - ah, how I laughed! I never had the steel for my role, but Harry Potter shall be more than equal to it, when he comes into his power." Albus Dumbledore's smile disappeared. "Though I suppose Harry shall have to find some other Dark Lord to vanquish for it, since you will not be there."

"Ah, yes. That." Professor Quirrell made to walk away from the Mirrror, and seemed to halt just before reaching the point where the Mirror would no longer have reflected him, if it had been reflecting him. "Interesting."

Dumbledore's smile was colder, now. "No, Tom. You are not going anywhere."

Professor Quirrell nodded. "What have you done, exactly?"

"You have refused death," said Dumbledore, "and if I destroyed your body, your spirit would only wander back, like a dumb animal that cannot understand it is being sent away. So I am sending you outside Time, to a frozen instant from which neither I nor any other can return you. Perhaps Harry Potter will be able to retrieve you someday, if prophecy speaks true. He may wish to discuss with you just who is at fault for the deaths of his parents. For you it will only be an instant - if you ever return at all. Either way, Tom, I wish you the best of it."

"Hm," said Professor Quirrell. The Defense Professor had paced past where Harry stood, watching mute and with something like horror, only to halt again at the other edge of the mirror. "As I suspected. You are using Merlin's old method of sealing, what the tale of Topherius Chang names as the Process of the Timeless. If legend speaks true, not even you can stop the process, now that it has been in motion this long."

"Indeed," said Albus Dumbledore. But his eyes were suddenly wary.

And Harry, from where he stood just before and to the right of the door, waiting in silence and controlled terror, could feel it in the air; he could feel the sense of a _presence_ gathering within the Mirror's field. Something more alien than magic, everything about it incomprehensible except for the fact of its strangeness and the fact of its power. It had been slow but now it was waxing faster, that presence.

"But you could still reverse the effect, if Chang's account is true," said Professor Quirrell. "Most powers of the Mirror are double-sided, according to legend. So you could banish what is on the other side of the Mirror instead. Send yourself, instead of me, into that frozen instant. If you wanted to, that is."

"And why would I do that?" Albus Dumbledore's voice was tight. "I suppose you are going to tell me that you have taken hostages? That was futile, Tom, you _fool!_ You utter _fool!_ You should have known that I would give you nothing for any hostages you had taken."

"You always were one step too slow," said Professor Quirrell. "Allow me to introduce you to my hostage."

Another presence invaded the air around Harry, a crawling sensation all over his flesh as another Tom Riddle's magic passed very close to his skin. The Cloak of Invisibility was torn away from him, and the shimmering black Cloak flew away from him, through the air.

Professor Quirrell caught it, and swiftly drew it over himself; in less than a second he had pulled down the Cloak's hood over his head, and disappeared.

Harry felt the sense of doom decrease suddenly as the Circle of Concealment around him disappeared.

Albus Dumbledore staggered, as though some essential support had been removed from him.

"Harry Potter," the Headmaster breathed. " _What are you doing here?_ "

Harry stared at the image of Albus Dumbledore, on whose face utter shock and utter dismay were warring.

 _A final sacrifice, before the world can be made better,_ thought Harry. _I am so sorry._

The guilt and the shame were hitting Harry all at once, and he could feel the incomprehensible presence around him rising to a peak. Even though he knew this was the right thing to do, it still hurt so much to actually go through with it.

"It's my fault," Harry said in a tiny voice, from whatever part of him had taken over pretending to be an innocent child in this final extremity. "I was stupid. I've always been stupid. You mustn't rescue me. Goodbye."

"Why, look at that," sang out Professor Quirrell's voice from the empty air, "I don't seem to have a reflection any more."

"No," said Albus Dumbledore. "No, no, _NO!_ "

Into the hand of the Albus Dumbledore flew from his sleeve his long, dark-grey wand, and in his other hand, as though from nowhere, appeared a short rod of dark stone.

Albus Dumbledore threw these both violently aside, just as the building sense of power rose to an unbearable peak, and then disappeared.

The Mirror returned to showing the ordinary reflection of a gold-lit room of white stone, without any trace of where Albus Dumbledore had been.

* * *

The Dark Lord was laughing.

From the empty air came the voice of the Defense Professor laughing wildly, so high and terrible his laughter; it was Voldemort's laughter now, the Dark Lord's laughter beyond all hiding or restraint.

 _Step 1: Stone acquired._

"Ah, ah hah, ah hah hah ha! Professor Dumbledore, ah, Professor Dumbledore, such a fitting end to our game!"

 _Step 2: Largest threats to the plan, removed._

Another burst of wild laughter. "The wrong sacrifice even at the finish, for the piece you gave up everything to save was already in my possession! The wrong trap even from the beginning, for I could have abandoned this body at any time! Ah, hahahahaha, aha! You never did learn cunning, you poor old fool."

Harry squinted in the direction of the voice. "Did you even need me for anything else besides this?"

 _Time for step 3: convince Voldemort. Well, this isn't the hardest problem I have ever solved._

"Ahahahaha! Why, yes, little child, you were always along on this adventure as my hostage, it was your whole purpose in being here. Ha, hahahaha! You are decades too young to play this game against the real Tom Riddle, child." The Dark Lord drew back the hood of the Cloak, his head becoming visible, and began to remove the rest of the Cloak. "And now, boy, _you have helped me, yess indeed, and so it iss time to ressurrect your girl-child friend. To keep promisse._ "

The Dark Lord's smile was cold, cold indeed. "I suppose you have doubts? Mark well, I could kill you this instant, for there is no longer a Headmaster of Hogwarts to be informed of it. Doubt me all you wish, but remember that." The hand was once more holding the gun.

Harry smiled, putting on more confidence than he felt. "I wouldn't recommend that."

The Dark Lord chuckled. "Are you going to offer yourself as my trusty lieutenant? There is little benefit in that to me. Your oath to help me had ended just now, and I do not want you to interfere with what happens next. Now come along, foolish child."

Harry did not move from his spot. Instead, he put his hands into his pockets, and hissed, " _What I meant to ssay iss, if you kill me now you would perissh ass well. We have much to disscusss, Professsor._ "


	7. Chapter 7

The Dark Lord went still. " _Explain. Now._ "

After being a target for Professor Quirrell's amusement for the last two hours, Harry couldn't resist. "Well, you see, first things are born, then they live, and then they die..."

Professor Quirrell's eye twitched. " _Sstop with the jokess, child. What kind of trap iss thiss? How would I die? You have no wand, no itemss, and no help coming. Only wizardss sstrong enough to challenge me have perisshed. What can you do to me?_ "

"Ah, but you are missing the most important weapon that I have. _There iss a prophecy that I would desstroy all but a remnant of you, ass you well know. I believe that we sshould disscusss how it is to be entirely fulfilled, in a manner agreeable to both of uss._ "

"That prophecy has been fulfilled, you stupid child. If this is all you have, then stop wasting-"

" _Do not think it wass fulfilled, Professsor._ "

" _Why not?_ "

Harry shrugged. " _You have ssaid I desstroyed your body. But that iss jusst your body, not your sself. You posssesss all memoriess, all perssonality, all magic of your previouss incarnation. That iss not a remnant of you, but the whole you. Desstroying your body wass about ass relevant ass desstroying your clothess._ "

Professor Quirrell sighed, and seemed to relax. "I see. You came up with one interpretation of the prophecy, and believe it to be correct. Mister Potter, prophecies are extremely tricky things, and analysing them is never so simple. It is far too easy to latch onto your idea for its true meaning, and end up being wrong. I have learned that the hard way."

Harry shrugged again. "Well, there is little reason to argue. I have once heard that those who have heard the prophecy firsthand would know if it came to be fulfilled. I suspect that that is part of the magic of prophecy. And wouldn't you know"- Harry smiled- "Professor Snape just happens to be nearby. You could use legilimency or some other magic on him, explain the real events of that night, and see in his mind if he believes the prophecy to be complete. Shall we test it, Lord Voldemort?"

Professor Quirrell seemed to consider this. "I suppose we may as well fulfill your curiosity as we go. It shall take little time, and might prevent you from doing something stupid. _Now_ are you ready to go?"

* * *

And they left.

They went back out through the door into the Potions room, the Dark Lord banishing the returned purple fire with a stroke of his wand. They went through the chamber where the boggart had been, and the chamber of ruined chess statues, and through the burned door of the chamber of keys. The Dark Lord floated up through the trapdoor, and Harry struggled up afterward through the spiral staircase of leaves, the tendrils of the Devil's Snare twitching and then moving back as though afraid.

The part that was numb with grief and guilt took this opportunity to observe, speaking of obliviousness, that after events at Hogwarts had turned serious, they really really _really REALLY_ should have reconsidered the decision made on First Thursday, at the behest of Professor McGonagall, _not to tell Dumbledore about the sense of doom that Harry got around Professor Quirrell._ It was true that Harry hadn't been sure who to trust, there was a long stretch where it had seemed plausible that Dumbledore was the bad guy and Professor Quirrell the heroic opposition, but…

Dumbledore would have realised.

Dumbledore would have realised instantly.

And then nothing would have been solved. Professor Quirrell would have evaded capture, would have defeated Dumbledore after deciding to fight seriously, and people all over the world would have continued to die. Up until a rogue asteroid, or some other crisis nobody was preparing to counter, smashed into the earth and destroyed all human life on it. This way, there was some hope for a better result.

They passed the huge three-headed Inferi, and at a whispered word from the Dark Lord it collapsed over the trapdoor and became a corpse again.

They found Severus Snape still standing guard, who told them both that he was guarding the door, and that they must leave or he would deduct House points.

The Dark Lord grabbed Snape by the neck, stared into his eyes, and said " _Legilimens_ ".

Harry leaned against the wall near the forbidden corridor's entrance and prepared to wait.

Everything stayed still for some time. Finally, Professor Quirrell released Snape, with an angry scowl on his face. Severus staggered before he lifelessly drew himself up beside the door once more.

"I take it I was right?" said Harry.

" _Yess,_ " hissed Professor Quirrell, his gun suddenly in his hand, " _Now tell me why I sshould not kill you before you fulfill thiss prophecy ass well, sstupid child._ "

Harry raised his eyebrows. "I thought I already said? If you try to kill me, you would die as well. You have already fulfilled the first half of the prophecy, and it can't be fulfilled only halfway. Since I must destroy some part of you, and I can't do that if I die, the fulfillment of the prophecy must come before my death. Therefore, if you forcefully shorten my lifespan, you also shorten the time prophecy has to fulfill itself. This means that progressively less and less probable paths of fulfillment might happen. Do you really want to play dice with the universe?" Harry had somehow forced a chuckle from himself. "I think you would lose if you try."

"How exactly do you imagine this happening, boy?"

Harry frowned. Was Professor Quirrell's fear of death really making him less rational? "Any number of ways. For example, muggles know that a lot of physics relies on probability. There is a chance that all air in the room would collect on one side, leaving pure vacuum on the other. However, you never see it in reality, because the chance of it happening is so small it would pretty much never occur before the stars go out. But if you force reality's hand, well, anything can happen. I do not know how magic functions in that regard, but I imagine the situation is similar." Harry smiled. "Do you know, the sun too relies on probability for its energy output? Maybe its output temporarily grows by three orders of magnitude" - did Harry imagine it, or did Professor Quirrell flinch a little? - "and it scours the earth, destroying all your horcruxes, and leaving you with only the pioneer probe - a remnant of yourself."

" _You foolissh child_ ," Lord Voldemort hissed, voice cold and dangerous, " _you ssaid desstruction of the world wass not your desire_ -"

" _It iss not. Would not be up to me if you forced the chancess._ "

Professor Quirrell started pacing, frustration evident on his face.

Harry glanced around at the hallway around them. "Should we go back inside the cerberus room and put up some privacy wards? It would be a shame if we were found here."

Professor Quirrell slashed his wand to the side, and the door of the forbidden corridor slammed open, throwing Professor Snape aside. " _Go. Now._ "

* * *

Back inside the forbidden corridor entrance, Professor Quirrell banished the Cerberus' corpse into a corner with a casual flick of his wand, and spun around to face Harry. "You said you wanted to find a way to fulfill the prophecy in a way agreeable to both of us. What did you have in mind? Speak now."

Harry sat in the corner opposite the dead dog, and leaned against a wall. This day was currently tied with The Azkaban Fiasco for the amount of shocks he was suffering, and it was bound to only get worse. He closed his eyes, and focused. "Well, as far as I see it, there are three things that need to be solved before any complex plan, such as the deliberate fulfillment of the prophecy, can be attempted. I hope I am right that you have no desire to let something as ambiguous as "destruction of all but the remnant of" happen to you without your control over it?" He opened one eye and looked at Professor Quirrell, who was pacing across the room, face furrowed in deep thought.

" _Yess. Obvioussly._ "

"Ah, good. _The prophecy sspeaks nothing about me ssurviving thiss, so I too would be oppossed to leaving thiss to chance. Sseemss to imply our sspiritss would have to end up ssimilar. If you are dead, I am likely alsso._ " Harry closed his eye again, "Then the three things we have to solve are as follows. First, we have to agree on some final state of the world that would be agreeable to both of us. If one of us tries to optimise towards one thing, and another towards something else, this just isn't going to work. From what I know, prophecies are finicky things, and even a hint of disagreement could ruin everything."

"Granted. What are the other two?"

"Next, we'll have to find a way to ensure neither of us tries to defect against the other by betraying the agreement. We must be working in concert the whole way through, and if either of us is to be tempted with betrayal, they must know that to be a failure state. Parseltongue should help significantly in this."

Professor Quirrell just nodded.

"Finally, we would have to settle on an exact way to break the prophecy our way. I have some ideas concerning this already, but those are all rather futile if we do not come to agreement on the first two points. We might have to iterate over this cycle a couple of times too, if the implementation we choose would make some other part of the plan unfeasible. Did I miss anything?"

"Nothing that I could notice, " said Professor Quirrell, stopping in his pacing, "your reasoning makes sense, for all the good that it does us."

Harry opened his eyes. It helped, to state the problem so clearly. Now to solve it. As easy as killing dementors. "Let's start with the second one, as it seems the easiest to crack. Parseltongue, as far as I understand, only confirms what you currently believe. That is a weakness, in this case, as your beliefs might change unexpectedly with new information. Do you know of a better magic for this?"

Professor Quirrell tapped his cheek in thought, his voice taking on his usual lecturing cadence. "The usual method for enforcing compliance with an oath is, of course, the ritual of the Unbreakable Vow. There is little reason to seek for better magic in this regard, as it is about as close to perfection as it gets. If that was necessary, we could rather easily find a target who would sacrifice their magic, arrange the drama for another target to sacrifice their trust, and swear whatever oaths were required. Are you going somewhere with this, boy?"

Harry nodded. This confirmed his thinking so far. He hissed in return, " _Have a vague idea. Working through every sstep sslowly, to check for errorss."_

Professor Quirrell regarded him with a steady gaze. "Work quickly then. _I ssee no mutually beneficial ssolutionss mysself. No ssolutionss that benefit me at all, actually._ It would be best to attempt whatever you came up with while we are still within the looped time, and we have wasted enough time here already."

Harry nodded again. Time loops sure were handy, at least when they weren't predicting your own destruction. As long as they attempted the plan before old Harry time turned back to originally meet Professor Quirrell, they had an assurance that nothing too drastic would happen, because it did not happen.

Harry said, "The next issue we have to solve is one of goals. We'll need to settle on a single desired outcome for this day, and work towards it. I have an idea for how we can reach a compromise between our goals…"

Professor Quirrell's eyebrows rose "Really now? And you will simply accept that I would go on killing people whom I despise? Would you like me to teach you the horcrux ritual too, so that you could finally get a real use out of other people?"

Harry grimaced. "I won't like it, but compromise implies both sides don't walk away perfectly happy. I'll accept that, as long as you will work with me to turn people you call idiots into non-idiots."

Professor Quirrell rolled his eyes. "Mister Potter, if educating people-"

"Not talking about education. I mean bioengineering."

"Pardon?"

Harry sighed. Professor Quirrell's knowledge of science fiction was really deficient, wasn't it.

"Use muggle science, probably in combination with magic, to tweak the brains of people until they are smarter than people of previous centuries. Muggles are perhaps half a century at most away from doing it, and I imagine could get there much faster if they knew about magic. Which we do. So we can get there faster. I presume that you would prefer never meeting idiots to meeting them, getting annoyed by them, and then killing them, yes?"

The idea seemed to send Professor Quirrell into a contemplative mood, as he gazed into space somewhere above Harry's head.

"Now, where was I?" said Harry. "Ah yes. Unfortunately, my idea relies on a certain model of you that seems contradictory with what is happening. You have said you wanted a second Tom Riddle to play against. There is now nothing I can really do to threaten you directly, and you didn't know about the unfulfilled prophecy until just a couple minutes ago. Furthermore, you have said you would resurrect Hermione. And yet, I cannot help but think that you were telling me more than you should, as if my lifespan was only measured in hours. Why do you want to kill me? If you do not, you can always deny it in parseltongue."

The Dark Lord regarded Harry with a grim look, then sighed. "Well, there is little reason to keep this to myself now, since you are so close to guessing the true answer. _When girl-child died, wass in company of sschool'ss Sseer, heard prophecy sspoken that you would become force of vasst desstruction. You would become threat beyond imagination, beyond apocalypsse. That iss why I went to ssuch lengthss to undo my killing of girl-child, keep it undone. Dare not ssay sspecificss to you. Prophecy I heard of mysself led me to fulfill it. Have not forgotten that dissasster."_

Cold chill went down Harry's spine. He screwed up some things in his life, but that…that was something else entirely.

Professor Quirrell continued speaking _. "All thiss, all I have done, iss to ssmassh that desstiny at every point of intervention. We would have been on our way to ressurrecting girl-child and making you sswear unbreakable oath that you sshall not desstroy the earth by now, if not for thiss. Now I can not kill you, for fear of prophecy. Can not avoid killing you, for fear of another prophecy. If you ssay you have ssolution to thiss, let alone one that ssatissfiess both of uss, tell me of it. You know well enough I would ssacrifice almosst anything to avoid either of the fatess that involve my death."_

Harry considered this new information, dread slowly descending over him. If he was prophesied to destroy the world… Well, most of his plans would go up in flames. It was one thing to experiment with magic if you thought Wizards missed something. It was another to keep doing so if the universe itself was telling you you were destined to screw up.

He swallowed, and said, "Well. If what you say is true, I am honestly not sure I should continue my line of reasoning anymore."

Professor Quirrell's eye twitched, his face momentarily screwing up in fury. "Mister Potter, I refuse to believe that your original plan involved anything bordering on the destruction of the world. Whatever quirk of fate that prophecy is about, it is unlikely to result from this plan of yours. Stop wasting time and speak!"

"Um. I would really really rather not play games with prophecies. If you, having accounted for me being better at dissecting the previous prophecy, still think it more likely that I would destroy the world if I hear it than if I don't… Well, frankly, I trust your judgement in this. And all that I know about the prophecy is that I somehow destroy the world directly. It seems like the best policy in that case is to not attempt direct actions at all."

" _You ssaid not fulfilling the firsst prophecy could desstroy the ssun, idiot-child of foretold desstruction! Now I tell you of another prophecy that ssayss you would desstroy the world, and your ansswer is to not go through with fulfilling the firsst?_ "

Harry shook his head. " _Do not think that would really happen. Think time triess to minimisse ssome kind of improbability meassure when acting, sso fulfillment would first... attempt to happen through the least improbable path, if it can. Ssomething like the ssun exploding iss so improbable ass to not be worth conssidering, really. Only mentioned it to sshow pathss to your death exisst, not ass an example of a path that iss likely."_

Professor Quirrell hissed in utter frustration, the sound as cold as liquid nitrogen.

Harry shrugged. "Sorry, I suppose. I won't risk the fate of the world for your life. If you want my analysis, you should decide whether you want to risk me knowing the prophecy, or whether you want to risk letting the prophecy of your destruction be fulfilled uncontrollably, or whether you want to try to get the idea out of my head somehow, with all the issues that causes. It would be a shame if some crucial detail got lost in translation from someone reading my mind, and then you reading theirs, for example."

For a while, everything stayed still in the room. Then, without Professor Quirrell even making a single gesture, the corpse of the cerberus lit up with a deadly silver flame and burned into nothing in mere moments. Harry tried to desperately scramble back from the sudden spike in the sense of doom that provided, but he was already as far as he could be without burrowing through the walls.

" _Lissten well, foolissh child,_ " hissed Professor Quirrell, " _lissten well, sso that if you later find yoursself sstanding above the asshess of the dead world, you would know your hand brought it about. Lissten, and do not sspeak of it in anything but parsseltongue, so that no other may know of it. The prophecy I heard sspoke thuss: He iss here. The one who will tear apart the very sstarss in heaven. He iss here. He iss the end of the world. Thiss iss all. Do you now have ssome kind of brilliant idea I have not had concerning thiss?_ "

A stone fell from Harry's heart.

"Ah. Well. _Ass far ass propheciess of the world ending go, that iss probably the besst, leasst terrifying one._ "

" _Explain._ "

" _Thiss is part of muggle knowledge you do not yet possesss. There iss a method, a processs you can usse to take a sstar apart for building materialss. Iss called sstar lifting. For muggless it iss only theory, but lawss of nature allow for it. Needss a lot of resourcess to even be sstarted. Desspite what you might think, it iss ssafe. Doess not causse sstarss to explode like bomb. Tearss them apart sslowly, like dissmantling a housse brick by brick, in reversse of how you've built it. By thosse who know of it, it iss sseen ass a ssign that humanity hass won. Becausse if it iss ever attempted, that meanss humanity hass sspread to multiple sstars, which would make it impossible for any ssingle catasstrophe to entirely wipe it out. Any catasstrophe known to muggless, anyway._ "

Professor Quirrell considered this silently for a while, then hissed, " _Even if you take that part of the prophecy out, you are sstill ssaid to be the end of the world. What do you ssay to that? You ssaid you cared about the world sso much, that you would not have been able to sswear to help me if you did not know I wassn't going to desstroy it. Iss the possibility of yoursself doing that not worth conssidering?_ "

Harry shrugged. " _I am sshaken by the prophecy mysself. Admit ssignificant chance of an apocalypsse. But it iss far from certain. Other interpretationss could fit too. It could sspeak of the magical world, and mean the current lifesstyle, the culture, which I would change greatly. Think thosse other interpretationss, when taken together, would add up to ssomething fairly ssignificant. Musst actively channel fate into thosse outcomess, not meekly accept defeat. Part about the sstarss sseemss to ssupport thiss too, I think. Only other way I can think of tearing apart sstarss iss new magic ressearch, and I can agree not to do that personally. Would agree to an oath you mentioned, ass well ass any other contingenciess you have in mind. Would even agree to whatever would let you kill me ssafely if that becomess necessary. Jusst becausse I am mentioned in one apocalypsse, doess not mean other apocalypsse can not happen in the meantime. A ssingle rock from void between sstarss can desstroy all life on earth, and there iss nothing that would sstop it at the moment. Think I could help ssignificantly to prevent ssuch catasstrophiess. Pluss, two Tom Riddless working on a problem iss better than one._ "

" _And you won't be convinced otherwisse?_ "

" _Don't think sso._ "

Professor Quirrell hummed. " _I ssuppossse thiss iss the besst I can hope for then._ "

"What would my vow be, in any case? The specific wording? Might be I'll see some loophole you've missed."

Professor Quirrell shook his head. "The vow doesn't work like that. It takes intent, not a trick of words. I will speak in plain speech, so the meaning is more clear. The intent of the vow was to be such: You will swear not to destroy the world, to take no risks when it comes to not destroying the world. This Vow may _not_ force you into any positive action, on account of that, this Vow does not force your hand to any stupidity. We must be cautious that this Vow itself does not bring that prophecy about. We dare not let this Vow force you to stand idly after some disaster is already set in motion by your hand, because you must take some lesser risk if you try to stop it. Nor must the Vow force you to choose a risk of truly vast destruction, over a certainty of lesser destruction." Voldemort's voice climbed higher, "You shall not gamble with the Earth's fate, so no researches that might lead to catastrophe, no unbinding of seals, no opening of gates!" Voldemort's voice lowered again. "Unless this very Vow itself is somehow leading into the destruction of the world, in which case, Harry Potter, you must ignore it in that particular regard. You will _not_ trust yourself alone in making such a determination, you must confide honestly and fully in your trusted friend, and see if that one agrees. And in myself, too. Such is this Vow's meaning and intent. It forces only such acts as you might choose yourself, having learned that you are a prophesied instrument of destruction. _And thiss iss true oath I would have made you sswear._ "

Harry considered it, then nodded. "It is a pretty thorough oath. We are in agreement then? _You will help me sswear thiss oath. I sshall help you ssurvive the fulfillment of the firsst prophecy. And after that, we would work together on ssafeguarding the world from variouss catasstrophiess._ "

Professor Quirrell sighed. "That is an excellent plan mister Potter, contingent on you coming up with a way to kill me without killing me. Did you have any brilliant ideas yet?"

"No. Let me think for five minutes."

Professor Quirrell shrugged. "We should still have more than three hours remaining in the time loop. I estimate you making the oath would take at most an hour, so you have time."

Harry nodded, and closed his eyes again.

Professor Quirrell has said that he could see no solution to this problem. This actually made things significantly simpler for Harry. All he had to do was search through the solution space that Professor Quirrell _wouldn't_ have considered due to his unique biases.

What wouldn't Professor Quirrell think of…

Back when Harry was in Azkaban, he confronted his Dark Side about the subject of death, and found it to be absolutely terrified of the prospect, so much so it was unable to reason clearly about anything related to it… but those were just neural pathways he inherited from Voldemort. It therefore stood to reason that Lord Voldemort was equally afraid of his demise, and would be unable to think rationally about the prospect, which seemed to fit the events of this day fairly well. As far as Harry knew, this was the only major bias Professor Quirrell possessed. And that meant Harry could limit his search only to ideas related to the death of Lord Voldemort.

How would you go about killing Lord Voldemort, if you actually had to do it?

Professor Quirrell said he made more than a hundred horcruxes. That had been insane, there wasn't any other word for it. A Muggle security expert would have called it fence-post security, like building a fence-post over a hundred metres high in the middle of the desert. Only a very obliging attacker would try to climb the fence-post. Anyone sensible would just walk around the fence-post, and making the fence-post even higher wouldn't stop that.

Once you forgot to be scared of how impossible the problem was supposed to be, it wasn't even difficult, not by comparison to the sort of problems Harry had solved before.

Neville's parents, for example, had been Crucioed into permanent insanity. Two hundred advanced horcruxes wouldn't prevent that insanity, they would all just echo the same damaged mind.

Obliviation. Unbreakable Oath. Confundus. Legilimency, if there was some way to break through Quirrell's perfect Occlumency barriers. Any other magic that altered, destroyed, or otherwise affected the mind. None of those would be stopped by Voldemort's horcrux network. It was quite ironic that in his efforts to protect against being killed Voldemort had left himself vulnerable to being Obliviated into a catatonic vegetable. He had to stay capable of Obliviating himself of the locations of the horcruxes he portkeyed into the sea, after all.

How could you destroy "all but the remnant" of someone?

A million ways to do that. Take whatever belongs to them that you can think of, and reduce it to almost nothing. Obliviate their entire memories, except for one. Annihilate their personality. Destroy everything they care about, and leave them a living husk of a person. Break their body so much they would be chained to the bed for the rest of their life.

How could you destroy "all but the remnant" of someone, without effectively killing them? That, was much harder.

Harry could see only a couple of different ways to do that, a couple of interpretations of the prophecy that could be brought into fruition. And only one of those could be performed within two hours.

Harry opened his eyes once more.

The Dark Lord Voldemort was staring at him with an expectant expression.

"Professor," said Harry, "how does the Unbreakable Vow ritual work, exactly?"

* * *

According to Professor Quirrell, an Unbreakable Vow required three people. One person sacrificed their magic to bind the vow. Another, sacrificed their trust in the vow-taker. And the last one, the one who was taking the vow, sacrificed their capability of choice. The sacrificed trust shaped the sacrificed magic, and that magic bound the vow-taker.

In other words, the magic of the one who was sacrificing his trust never directly touched the magic of the vow-taker. And that meant Tom Riddle senior could swear a vow to Harry, even if that would be incredibly painful to both of them. The magic of the vow-binder would not go into resonance with their magics, after all.

"So let me see if I understood you correctly", said Lord Voldemort, "You propose that I swear an oath to _you_. And in that oath I would..."

"Swear to become your mask of professor Quirrell in truth, yes."

"And why, exactly, do you think this would fulfill the prophecy?"

"Well," said Harry, "you have once told me that identity does not mean, to such as us, what it means to other people. Anyone you can imagine, you can be. Any mask, any role, whatever is necessary or simply amusing at the time. You are a thousand different masks, and I propose you to be reduced to just one."

"Which would destroy all but a remnant of me. I see..." Tom Riddle paced around the room, finger tapping his cheek in contemplation.

Harry shrugged, and winced a bit at the soreness in his shoulders from all the shrugging he did today. " _It fitss, I think._ The mask of professor Quirrell is very similar to my spirit, and our goals are already aligned. It would limit you somewhat, but that is the most acceptable outcome, as far as I can see. You, on the other hand, enjoyed teaching as far as I could tell, and some drama could be arranged to explain why you are no longer sick."

Professor Quirrell nodded. "I admit that ideas of self-sacrifice do not come easily to me, so your input was supremely helpful. We could later check if Snape would consider such an oath to be a fulfilment of the prophecy, and plan accordingly if it nonetheless fails."

Harry nodded. "Precisely. I think we should resurrect Hermione first, and then make me swear my oath, just to be sure we are not missing something destructive here. Do you know where we could find a magic-donor? I presume you have a way of getting one, since you intended to make me swear an oath today."

"I intended to summon the death eaters from outside of the castle wards. One of them could serve as the vow-binder, and another could sacrifice his trust. I see no reason to change that part of the previous plan. They shall also serve for the drama of Voldemort's return and swift defeat, as I have mentioned to you after the Azkaban fiasco. This would immediately put us in power over Britain, if done right, which should be useful for later plans. Now, how to arrange the spectacle..."

One idea was discussed, and then another. A dozen minutes swiftly passed, as the final details of the plan were ironed out. The dramatic return of Lord Voldemort (complete with snake-eyes and special effects) was sketched out, no detail too small to consider, until finally, The Boy Who Lived and The Dark Lord Voldemort came to an agreement. And then, there was nothing left to discuss anymore.

Harry stood up. "Well," he said, "let's get to work. Time to make this happen."

They walked out of the door, and step one of their plan began.

 **Author Notes:**

* * *

 **This concludes Unriddle the Riddles. I currently do not intend to write a further continuation, though everything is possible later down the line, of course. Should someone decide to take up the torch themselves, you have my full permission to do so.**

 **Thanks for reading, and if you ever meet an immortal dark wizard, don't forget your decision theory!**


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